Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/25/13
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
440 PM MST SAT AUG 24 2013
.UPDATE...AVIATION DISCUSSION.
&&
.SYNOPSIS...
A STORMY PERIOD IS ANTICIPATED THIS WEEKEND ACROSS THE REGION WITH
BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED FLOODING MAY
OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT WEEK...AND
INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF THE
WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.
&&
.DISCUSSION...
WET AND UNSETTLED WEATHER SCENARIO DEVELOPING THIS AFTERNOON PRETTY
MUCH AS EXPECTED...AS MOISTURE FROM TROPICAL SYSTEM IVO CONTINUES TO
SHED TO THE NORTH AND INTO ARIZONA AND SE CALIFORNIA. BEST
MLCAPE/SURFACE BASED CAPE VALUES ARE LOCATED ACROSS SERN CA AND SWRN
AZ. PWAT VALUES ARE UP...WITH PHOENIX REPORTING 1.6 INCHES ON THE
MORNING RAOB. SURFACE DEWPOINTS AT 2 PM RANGED FROM THE MID 5OS TO
MID 60S OVER THE CENTRAL AZ DESERTS...TO THE MID 60S TO LOW 70S OVER
PORTIONS OF IMPERIAL COUNTY. STRONG THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON WEST OF THE LOWER CO RIVER VALLEY WHERE
INSTABILITY IS GREATEST...AND THEY HAVE PRODUCED VERY HEAVY
RAINFALL. RADAR INDICATED OVER 4 INCHES OF RAIN FELL WEST OF THE
SALTON SEA DURING THE EARLY AFTERNOON. STRONG CONVECTION CAN BE
EXPECTED FOR THE REST OF THE AFTERNOON AND INTO THE EVENING HOURS
OVER OUR WESTERN DESERTS.
MLCAPE VALUES ARE MUCH LOWER OVER SOUTH CENTRAL AZ...MOSTLY LESS
THAN 600 J/KG...SO LESS CONVECTION IS EXPECTED. HOWEVER THERE HAS
BEEN QUITE A BIT OF SUNSHINE SOUTH AND EAST OF PHOENIX THIS MORNING
AND EARLY AFTERNOON AND STORMS WILL LIKELY START TO GENERATE AND
MOVE NORTH INTO OUR AREA LATER THIS AFTERNOON AND INTO THE EVENING
HOURS. THUS...WE WILL STILL CALL FOR NEARLY 50 PERCENT CHANCE OF
THUNDERSTORMS TONIGHT OVER OUR EASTERN ZONES. OTHERWISE...FORECASTS
APPEAR ON TRACK AS MOISTURE FROM DECAYING IVO WILL SPREAD INTO THE
CWA LATER TONIGHT...WITH PWAT VALUES MAXING SUNDAY INTO SUNDAY
NIGHT...IN AREAS WEST OF MARICOPA COUNTY. POPS WILL REMAIN ELEVATED
THRU SUNDAY NIGHT...MOSTLY IN THE 60 TO 80 PERCENT BALLPARK. LESS
INSTABILITY EXPECTED SUNDAY/SUNDAY NIGHT SO STORMS WILL BE LESS
SEVERE BUT THE THREAT FOR HEAVY RAIN WILL BE INCREASED DUE TO PWAT
VALUES THAT WILL CLIMB WELL ABOVE 2 INCHES. FLASH FLOOD WATCH WILL
CONTINUE FOR ALL ZONES WEST OF ZONE 23 STARTING AT 11 PM TONIGHT AND
CONTINUING THRU 11 PM SUNDAY NIGHT. LITTLE CHANGE MADE BEYOND SUNDAY
NIGHT...AS MOST OF THE EFFORTS TODAY HAVE BEEN CHASING ONGOING
FLOODING AND SEVERE WEATHER EPISODES. FOLLOWING DISCUSSION IS A MORE
DETAILED ANALYSIS FROM THE MID SHIFT.
PREVIOUS DISCUSSION...A BATCH OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE METRO AREA EARLY THIS MORNING. LATEST RUC
IDENTIFIES A PERTURBATION MOVING THROUGH THE SOUTH-CENTRAL ARIZONA
DESERTS WHICH MIGHT ACCOUNT FOR THIS. THERE WAS A GRAVITY WAVE THAT
MOVED THROUGH BUT THAT WAS AT LEAST A FEW HOURS AGO. THE RUC SHOWS
THE PERTURBATION SHIFTING NORTH AFTER 12Z AND THUS STORM ACTIVITY
OVER MARICOPA COUNTY SHOULD WIND DOWN SHORTLY AFTER
SUNRISE...ALREADY QUIET ELSEWHERE IN THE FORECAST AREA. LARGER SCALE
FLOW FEATURES OF NOTE INCLUDE THE EVER-PRESENT TROUGH CENTERED NEAR
THE WEST COAST...A LARGE ANTICYCLONE/RIDGE CENTERED OVER THE
PLAINS...AN INVERTED TROUGH CENTERED NEAR THE CHIHUAHUA/TEXAS
BORDER...AND TROPICAL STORM IVO CENTERED WEST OF CABO SAN LUCAS. THE
MODELS HAVE DIFFERING SOLUTIONS ON HOW THE FLOW FEATURES MENTIONED
ABOVE WILL UNFOLD...PARTICULARLY THE INVERTED TROUGH AND THE BROADER
CYCLONIC CIRCULATION ASSOCIATED WITH IVO. FOR INSTANCE...THE GFS
CONTINUES TO TRACK THE IVO ASSOCIATED CIRCULATION TO THE NORTH
FASTER THAN ECWMF AND ESPECIALLY NAM. BY THAT SAME TOKEN...THE WAVE
ALSO DISSIPATES FASTER. THIS HAS IMPLICATIONS FOR TIMING OF
POPS/PRECIP. THERE ARE ALSO DIFFERENCES ON THE UPPER LEVEL
DIVERGENCE GENERATED BY THE APPROACHING WAVE WHICH ALSO IMPACTS
MODEL PRECIP FORECASTS. THOUGH THE NAM IS SLOWER WITH THE IVO
CIRCULATION...IT BRINGS IN A SMALLER WAVE LATER TODAY WHICH MIGHT BE
REMNANTS OF THE INVERTED TROUGH AND/OR A CONVECTIVELY GENERATED
FEATURE FROM SOUTHERN SONORA. THE NAM THUS PRODUCES A BATCH OF
DYNAMICAL FORCING SOONER THAN THE GFS AND ECWMF. THEY ALL SHOW A
MAJOR INFLUX OF MOISTURE. INTERESTINGLY...THERE ARE SOME
SIMILARITIES IN THE SPATIAL DISTRIBUTION OF THE QPF...INCLUDING
LOCAL WRF AND NMM6KM. MAINLY...FROM TONIGHT THROUGH SUNDAY NIGHT
THERE IS A HIGH QPF SWATH OVER WESTERN MARICOPA COUNTY AND SOUTHWEST
ARIZONA. AND A LESSER SWATH OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. IN BETWEEN IS A LOWER QPF SWATH...INCLUDING THE PHOENIX
METRO AREA. HOWEVER...THERE IS A GREAT DEAL OF VARIABILITY FOR
SOUTHEAST CALIFORNIA. THE GFS HAS ITS HEAVIEST SWATH...FOR OUR
FORECAST AREA...OVER EASTERN RIVERSIDE AND IMPERIAL COUNTIES. MADE
NUMEROUS ADJUSTMENTS TO THE QPF AND POP GRIDS. MODIFIED THE FLASH
FLOOD WATCH TO START IT 6 HOURS EARLIER AND TO EXTEND IT EASTWARD
OVER WESTERN MARICOPA COUNTY. IT SHOULD BE NOTED THAT WE WILL NOT
HAVE A TROPICAL STORM THAT BODILY MOVES INTO THE DESERT SOUTHWEST.
RATHER...TROPICAL MOISTURE WILL BE PUSHED NORTHWARD INTO THE REGION
AND THERE WILL BE FLOW FEATURES AIDING THE PRECIPITATION PRODUCTION.
ALSO...WHILE THE WATCH DOES NOT START UNTIL 06Z...THERE WILL LIKELY
BE SOME POTENT THUNDERSTORMS DEVELOPING WITHIN OUR AREA PRIOR TO
THAT. THE GFS...NAM...AND SREF ALL HAVE CAPE VALUES WELL IN EXCESS
OF 1000 J/KG...MAINLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. PRIOR TO THE ARRIVAL OF BROADER SCALE LIFT...ANTICIPATE
STORMS BEING MORE SCATTERED IN NATURE AS OPPOSED TO WIDESPREAD RAIN.
WITH HIGH CAPE VALUES...THERE WILL BE SEVERE POTENTIAL LATE THIS
AFTERNOON AND EVENING. THEREAFTER...ANTICIPATE DECREASING CAPE BUT
MORE WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS. WITH THE CLOUDS
AND RAIN COOLED AIR AROUND...SUNDAY TEMPS WILL BE WELL BELOW NORMAL.
EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
THROUGH 06Z SUN...LIGHT VRBL WINDS. SCT-BKN CLOUDS 10-15 THSD MSL.
11Z SUN THROUGH 23Z SUN...INCREASING CLDS BCMG 8-10 THSD BKN MSL...
WITH A CHANCE OF SHWRS AND TSTMS.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWERS AND THUNDERSTORM ARE EXPECTED TO IMPACT KIPL THIS
AFTERNOON...AND KBLH EARLY THIS EVENING ARE CONVECTIVE ACTIVITY
BREAKS OUT AS A VERY MOIST AIRMASS BECOMES ENTRENCHED ACROSS THE
REGION. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG GUSTY WINDS
AND PERIODS OF HEAVY RAIN AS THEY PASS OVER THE TERMINALS. LIKELY
SHOWERS...AND PERHAPS A PERIOD OF STEADY RAIN IS LIKELY LATER
TONIGHT AND ON SUNDAY AS THE AIRMASS STABILIZES OUT...BUT STILL
REMAINS VERY MOIST...WITH BKN TO OVC MID-LEVEL CIGS WIDESPREAD OVER
THE REGION.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
DEEP SOUTHERLY FLOW IS EXPECTED TO BRING IN ABOVE-AVERAGE AMOUNTS OF
MOISTURE INTO THE REGION THROUGH THE FORECAST PERIOD...WITH ISOLATED
TO SCATTERED THUNDERSTORMS LIKELY EACH AFTERNOON AND EVENING.
MINIMUM HUMIDITY VALUES ARE EXPECTED TO FALL INTO THE 25 TO 35
PERCENT RANGE ACROSS THE LOWER DESERTS...AND INTO THE 35 TO 45
PERCENT RANGE ACROSS THE HIGHER ELEVATIONS EACH DAY...WITH VERY GOOD
TO EXCELLENT OVERNIGHT RECOVERIES. WINDS ARE EXPECTED TO REMAIN ON
THE LIGHT SIDE...EXCEPT NEAR THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY
EVENING AZZ020-021-022-025-026-027.
CA...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY
EVENING CAZ030>033.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CB
PREVIOUS DISCUSSION...AJ/DEWEY
AVIATION...VASQUEZ/PERCHA/LEINS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1235 PM MST FRI AUG 23 2013
.SYNOPSIS...
INCREASING MOISTURE AND PRECIPITATION CHANCES TODAY THROUGH
MONDAY...AS WELL AS A DECREASE IN TEMPERATURES. INCREASED
PRECIPITATION CHANCES WILL CONTINUE THROUGH MOST OF NEXT WEEK.
&&
.DISCUSSION...
MORNING SATELLITE IMAGERY LOOKS SIMILAR TO YESTERDAY...HOWEVER A BIT
LESS CLOUD COVER ACROSS THE STATE. LAST EVENING/S LARGE AREA OF
CONVECTION CAN BE SEEN ON RADAR MOVING INTO SOUTHWEST UTAH...AND
SOME STREAMS OF LINGERING SHOWERS ACROSS WESTERN MARICOPA COUNTY AT
10 AM MST. 12Z RAOB SOUNDING PWAT VALUES SHOW LITTLE CHANGE FROM
YESTERDAY WITH SLIGHT DRYING IN THE MID AND LOW LEVELS ACROSS THE
DESERT SOUTHWEST...VALUES 0.7 - 1.4 INCHES ACROSS ARIZONA. WITH THE
BOUNDARY LAYER WORKED OVER QUITE WELL IN THE SOUTHWEST CORNER OF
ARIZONA LAST EVENING...CONFIDENCE IS HIGHER MOST OF THE CONVECTIVE
ACTIVITY WILL REMAIN ACROSS MARICOPA COUNTY AND POINTS EASTWARD.
MADE SOME CHANGES TO THE POP GRIDS FOR THE REMAINDER OF
TODAY...INCREASING SPACIAL COVERAGE FOR SLIGHT CHANCES TO CHANCES
ACROSS THE LOWER DESERTS. TEMPERATURES SHOULD BE SET FOR NOW...ON
TRACK TO REACH SEASONAL NORMAL. MORE UPDATES LATER...AS THE PREVIOUS
DISCUSSION STILL APPLIES.
.PREVIOUS DISCUSSION.../246 AM MST/...
EVENING STORM ACTIVITY HAS LARGELY QUIETED DOWN ACROSS THE FORECAST
AREA THIS MORNING...WITH MOST OF THE STORMS SHIFTING NORTHWARD
OVER NORTHWEST ARIZONA AS OF 09Z. UPPER LEVEL DIFLUENCE IN AN AREA
OF 50+KT 250MB WINDS APPEARS TO BE THE DRIVING FORCE FOR THESE
STORMS AND WV IMAGERY SUGGESTS THE STORMS SHOULD REMAIN CONFINED TO
THE HIGHER TERRAIN NORTH OF THE CWA. LATEST RUN OF THE HRRR MODEL
WANTS TO CONTINUE RE-DEVELOPING STORMS AS FAR SOUTH AT YUMA THIS
MORNING...BUT THE BOUNDARY LAYER IS NO LONGER SUPPORTIVE OF STORMS
SINCE LAST EVENINGS CONVECTION. IN THE VERY SHORT TERM I WILL
MAINTAIN A 10-20 POP ACROSS LA PAZ AND FAR NORTHWEST MARICOPA COUNTY
IN THE EVENT THESE STORMS BACK-BUILD TO THE SOUTH...OTHERWISE NOT
EXPECTING MUCH STORM ACTIVITY FOR THIS MORNING.
TOUGH FORECAST FOR THIS AFTERNOON...AS THE TWO MOST RECENT RUNS OF
THE SREF PAINT A NEARLY IDENTICAL AREA OF ENHANCED MLCAPES ACROSS
WESTERN AND SOUTHERN ARIZONA. MEANWHILE...SLIGHTLY DRIER THAN NORMAL
AIR REMAINS IN PLACE FROM CENTRAL NEW MEXICO TO THE MOUNTAINS OF
EASTERN ARIZONA. HARD TO ENVISION STORMS FORMING IN THE IDENTICAL
AREAS TWO DAYS IN A ROW...ESPECIALLY GIVEN LITTLE RECOVERY TIME FROM
THURSDAYS CONVECTIVE OVERTURNING OF THE BOUNDARY LAYER.
NONETHELESS...I THINK STORMS ARE POSSIBLE ACROSS PORTIONS OF LA
PAZ...YUMA...AND WESTERN MARICOPA COUNTIES. NAMDNG5 AND NMM BASED
WRF MODELS ARE THE MOST VIGOROUS WITH THIS AFTERNOONS CONVECTION IN
THESE AREAS WHILE ARW BASED MODELS ARE A BIT MORE RESERVED.
INHERITED FORECAST DEPICTED 20-30 POPS WEST OF PHOENIX AND THIS
STILL LOOKS REASONABLE. TOUGH TO SAY HOW MUCH WILL DEVELOP EAST OF
PHOENIX. NOT MUCH IN THE WAY OF FORCING MECHANISMS OR SUBSTANTIAL
MOISTURE...BUT THERE IS DECENT POTENTIAL FOR MLCAPES AOA 1000 J/KG.
LEFT POPS IN THE 20-30 RANGE IN SOUTHERN GILA CO AS WELL.
THE WEEKEND STILL LOOKS TO BE QUITE ACTIVE ACROSS THE
REGION...SYNOPTIC SCALE MODEL AGREEMENT CONTINUES FOR AT LEAST THE
3RD OR 4TH DAY IN A ROW. ALL MODELS SUGGEST A SUBSTANTIAL INCREASE
IN MOISTURE ON SATURDAY WITH MIXING RATIOS CLIMBING INTO THE 10-12
G/KG RANGE...POSSIBLY TOPPING OUT ABOVE 14 G/KG. PWATS OF 2.0-2.2
INCHES WILL BE COMMON ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA THIS WEEKEND WITH SLIGHTLY LOWER VALUES TO THE EAST. THERE
ARENT ANY OBVIOUS TROUGHS DEPICTED IN THE FLOW DURING THE DAY ON
SATURDAY...BUT MID LEVEL SPEED CONVERGENCE BEGINS TO TAKE SHAPE LATE
SATURDAY NIGHT INTO SUNDAY MORNING. I REFINED POPS SLIGHTLY TO SHOW
THE HIGHEST VALUES FROM 00Z SUNDAY THROUGH 00Z MONDAY...CERTAINLY A
PRETTY LONG BROAD-BRUSHED PERIOD...BUT ONCE STORMS DEVELOP THEY
SHOULD HAVE NO PROBLEM MAINTAINING THEMSELVES ACROSS THE ENTIRE
REGION. POPS CWA-WIDE HAVE BEEN INCREASED INTO THE 60-80 PERCENT
RANGE. WOULD LIKE TO PLACE FURTHER TEMPORAL REFINEMENT INTO THE
FORECAST BUT IT WILL BE TOUGH UNTIL STORMS ACTUALLY BEGIN DEVELOPING.
UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND CONSEQUENTLY I
THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM COVERAGE
MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT FRIDAY
WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL TEMPS
GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE GFS AND
EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES NEXT
WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY PER
GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN PLACE...TUESDAY
AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF THESE TROUGHS
ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO NEED TO BE
LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.
&&
.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...INCLUDING KPHX...KIWA...KSDL...KIPL...AND KBLH...
CONDITIONS REMAIN MOIST AND ISOLATED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP THIS AFTERNOON ACROSS MUCH OF THE AREA. ACROSS
SOUTH-CENTRAL AZ...CONVECTION WILL BE CONCENTRATED ACROSS THE HIGHER
TERRAIN MAINLY EAST OF PHOENIX. AT THE PHOENIX TERMINALS...AN
OUTFLOW BOUNDARY IS LIKELY TO PRODUCE A WIND SHIFT THIS
EVENING...RESULTING IN AN EARLIER ONSET TO THE DRAINAGE FLOW.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...DEWEY
PREVIOUS DISCUSSION...LEINS
AVIATION...HIRSCH
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
1015 AM MST FRI AUG 23 2013
.SYNOPSIS...
INCREASING MOISTURE AND PRECIPITATION CHANCES TODAY THROUGH
MONDAY...AS WELL AS A DECREASE IN TEMPERATURES. INCREASED
PRECIPITATION CHANCES WILL CONTINUE THROUGH MOST OF NEXT WEEK.
&&
.DISCUSSION...
MORNING SATELLITE IMAGERY LOOKS SIMILAR TO YESTERDAY...HOWEVER A BIT
LESS CLOUD COVER ACROSS THE STATE. LAST EVENING/S LARGE AREA OF
CONVECTION CAN BE SEEN ON RADAR MOVING INTO SOUTHWEST UTAH...AND
SOME STREAMS OF LINGERING SHOWERS ACROSS WESTERN MARICOPA COUNTY AT
10 AM MST. 12Z RAOB SOUNDING PWAT VALUES SHOW LITTLE CHANGE FROM
YESTERDAY WITH SLIGHT DRYING IN THE MID AND LOW LEVELS ACROSS THE
DESERT SOUTHWEST...VALUES 0.7 - 1.4 INCHES ACROSS ARIZONA. WITH THE
BOUNDARY LAYER WORKED OVER QUITE WELL IN THE SOUTHWEST CORNER OF
ARIZONA LAST EVENING...CONFIDENCE IS HIGHER MOST OF THE CONVECTIVE
ACTIVITY WILL REMAIN ACROSS MARICOPA COUNTY AND POINTS EASTWARD.
MADE SOME CHANGES TO THE POP GRIDS FOR THE REMAINDER OF
TODAY...INCREASING SPACIAL COVERAGE FOR SLIGHT CHANCES TO CHANCES
ACROSS THE LOWER DESERTS. TEMPERATURES SHOULD BE SET FOR NOW...ON
TRACK TO REACH SEASONAL NORMAL. MORE UPDATES LATER...AS THE PREVIOUS
DISCUSSION STILL APPLIES.
.PREVIOUS DISCUSSION.../246 AM MST/...
EVENING STORM ACTIVITY HAS LARGELY QUIETED DOWN ACROSS THE FORECAST
AREA THIS MORNING...WITH MOST OF THE STORMS SHIFTING NORTHWARD
OVER NORTHWEST ARIZONA AS OF 09Z. UPPER LEVEL DIFLUENCE IN AN AREA
OF 50+KT 250MB WINDS APPEARS TO BE THE DRIVING FORCE FOR THESE
STORMS AND WV IMAGERY SUGGESTS THE STORMS SHOULD REMAIN CONFINED TO
THE HIGHER TERRAIN NORTH OF THE CWA. LATEST RUN OF THE HRRR MODEL
WANTS TO CONTINUE RE-DEVELOPING STORMS AS FAR SOUTH AT YUMA THIS
MORNING...BUT THE BOUNDARY LAYER IS NO LONGER SUPPORTIVE OF STORMS
SINCE LAST EVENINGS CONVECTION. IN THE VERY SHORT TERM I WILL
MAINTAIN A 10-20 POP ACROSS LA PAZ AND FAR NORTHWEST MARICOPA COUNTY
IN THE EVENT THESE STORMS BACK-BUILD TO THE SOUTH...OTHERWISE NOT
EXPECTING MUCH STORM ACTIVITY FOR THIS MORNING.
TOUGH FORECAST FOR THIS AFTERNOON...AS THE TWO MOST RECENT RUNS OF
THE SREF PAINT A NEARLY IDENTICAL AREA OF ENHANCED MLCAPES ACROSS
WESTERN AND SOUTHERN ARIZONA. MEANWHILE...SLIGHTLY DRIER THAN NORMAL
AIR REMAINS IN PLACE FROM CENTRAL NEW MEXICO TO THE MOUNTAINS OF
EASTERN ARIZONA. HARD TO ENVISION STORMS FORMING IN THE IDENTICAL
AREAS TWO DAYS IN A ROW...ESPECIALLY GIVEN LITTLE RECOVERY TIME FROM
THURSDAYS CONVECTIVE OVERTURNING OF THE BOUNDARY LAYER.
NONETHELESS...I THINK STORMS ARE POSSIBLE ACROSS PORTIONS OF LA
PAZ...YUMA...AND WESTERN MARICOPA COUNTIES. NAMDNG5 AND NMM BASED
WRF MODELS ARE THE MOST VIGOROUS WITH THIS AFTERNOONS CONVECTION IN
THESE AREAS WHILE ARW BASED MODELS ARE A BIT MORE RESERVED.
INHERITED FORECAST DEPICTED 20-30 POPS WEST OF PHOENIX AND THIS
STILL LOOKS REASONABLE. TOUGH TO SAY HOW MUCH WILL DEVELOP EAST OF
PHOENIX. NOT MUCH IN THE WAY OF FORCING MECHANISMS OR SUBSTANTIAL
MOISTURE...BUT THERE IS DECENT POTENTIAL FOR MLCAPES AOA 1000 J/KG.
LEFT POPS IN THE 20-30 RANGE IN SOUTHERN GILA CO AS WELL.
THE WEEKEND STILL LOOKS TO BE QUITE ACTIVE ACROSS THE
REGION...SYNOPTIC SCALE MODEL AGREEMENT CONTINUES FOR AT LEAST THE
3RD OR 4TH DAY IN A ROW. ALL MODELS SUGGEST A SUBSTANTIAL INCREASE
IN MOISTURE ON SATURDAY WITH MIXING RATIOS CLIMBING INTO THE 10-12
G/KG RANGE...POSSIBLY TOPPING OUT ABOVE 14 G/KG. PWATS OF 2.0-2.2
INCHES WILL BE COMMON ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA THIS WEEKEND WITH SLIGHTLY LOWER VALUES TO THE EAST. THERE
ARENT ANY OBVIOUS TROUGHS DEPICTED IN THE FLOW DURING THE DAY ON
SATURDAY...BUT MID LEVEL SPEED CONVERGENCE BEGINS TO TAKE SHAPE LATE
SATURDAY NIGHT INTO SUNDAY MORNING. I REFINED POPS SLIGHTLY TO SHOW
THE HIGHEST VALUES FROM 00Z SUNDAY THROUGH 00Z MONDAY...CERTAINLY A
PRETTY LONG BROAD-BRUSHED PERIOD...BUT ONCE STORMS DEVELOP THEY
SHOULD HAVE NO PROBLEM MAINTAINING THEMSELVES ACROSS THE ENTIRE
REGION. POPS CWA-WIDE HAVE BEEN INCREASED INTO THE 60-80 PERCENT
RANGE. WOULD LIKE TO PLACE FURTHER TEMPORAL REFINEMENT INTO THE
FORECAST BUT IT WILL BE TOUGH UNTIL STORMS ACTUALLY BEGIN DEVELOPING.
UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND CONSEQUENTLY I
THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM COVERAGE
MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT FRIDAY
WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL TEMPS
GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE GFS AND
EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES NEXT
WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY PER
GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN PLACE...TUESDAY
AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF THESE TROUGHS
ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO NEED TO BE
LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.
&&
.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...INCLUDING KPHX...KIWA...KSDL...KIPL...AND KBLH...
A WEATHER DISTURBANCE OVER WESTERN ARIZONA WILL KEEP CLOUDINESS...AT
OR ABOVE 12 KFT MSL...IN PLACE BETWEEN PHOENIX AND FAR SOUTHEAST
CALIFORNIA THROUGH THE MORNING BEFORE DECREASING THIS AFTERNOON.
SHOWERS WILL BE POSSIBLE IN THAT AREA WITH MORE ACTIVITY OVER
NORTHERN ARIZONA AND SOUTHERN NEVADA. ONCE AGAIN...OUTFLOW WINDS
FROM DISTANT STORMS WILL BE A DISTINCT POSSIBILITY LATER TODAY/THIS
EVENING. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS AT EACH OF
THE TAF SITES BUT LESS ACTIVITY IS ANTICIPATED OVER THE LOWER
COLORADO RIVER VALLEY AND THE IMPERIAL VALLEY THAN ON THURSDAY.
CONFIDENCE IN STORMS OCCURRING OVER ANY GIVEN TAF SITE TOO LOW TO
REFLECT IN THE TAFS AT THIS POINT. APART FROM THUNDERSTORMS...WINDS
WILL BE LIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...DEWEY
PREVIOUS DISCUSSION...LEINS
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
555 AM MST FRI AUG 23 2013
.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.
&&
.SYNOPSIS...
A GRADUAL INCREASE IN PRECIPITATION CHANCES...AS WELL AS A DECREASE
IN TEMPERATURES...IS EXPECTED OVER THE NEXT SEVERAL DAYS AND INTO
THIS WEEKEND. INCREASED PRECIPITATION CHANCES WILL CONTINUE THROUGH
EARLY NEXT WEEK.
&&
.DISCUSSION...
EVENING STORM ACTIVITY HAS LARGELY QUIETED DOWN ACROSS THE FORECAST
AREA THIS MORNING...WITH MOST OF THE STORMS SHIFTING NORTHWARD
OVER NORTHWEST ARIZONA AS OF 09Z. UPPER LEVEL DIFLUENCE IN AN AREA
OF 50+KT 250MB WINDS APPEARS TO BE THE DRIVING FORCE FOR THESE
STORMS AND WV IMAGERY SUGGESTS THE STORMS SHOULD REMAIN CONFINED TO
THE HIGHER TERRAIN NORTH OF THE CWA. LATEST RUN OF THE HRRR MODEL
WANTS TO CONTINUE RE-DEVELOPING STORMS AS FAR SOUTH AT YUMA THIS
MORNING...BUT THE BOUNDARY LAYER IS NO LONGER SUPPORTIVE OF STORMS
SINCE LAST EVENINGS CONVECTION. IN THE VERY SHORT TERM I WILL
MAINTAIN A 10-20 POP ACROSS LA PAZ AND FAR NORTHWEST MARICOPA COUNTY
IN THE EVENT THESE STORMS BACK-BUILD TO THE SOUTH...OTHERWISE NOT
EXPECTING MUCH STORM ACTIVITY FOR THIS MORNING.
TOUGH FORECAST FOR THIS AFTERNOON...AS THE TWO MOST RECENT RUNS OF
THE SREF PAINT A NEARLY IDENTICAL AREA OF ENHANCED MLCAPES ACROSS
WESTERN AND SOUTHERN ARIZONA. MEANWHILE...SLIGHTLY DRIER THAN NORMAL
AIR REMAINS IN PLACE FROM CENTRAL NEW MEXICO TO THE MOUNTAINS OF
EASTERN ARIZONA. HARD TO ENVISION STORMS FORMING IN THE IDENTICAL
AREAS TWO DAYS IN A ROW...ESPECIALLY GIVEN LITTLE RECOVERY TIME FROM
THURSDAYS CONVECTIVE OVERTURNING OF THE BOUNDARY LAYER.
NONETHELESS...I THINK STORMS ARE POSSIBLE ACROSS PORTIONS OF LA
PAZ...YUMA...AND WESTERN MARICOPA COUNTIES. NAMDNG5 AND NMM BASED
WRF MODELS ARE THE MOST VIGOROUS WITH THIS AFTERNOONS CONVECTION IN
THESE AREAS WHILE ARW BASED MODELS ARE A BIT MORE RESERVED.
INHERITED FORECAST DEPICTED 20-30 POPS WEST OF PHOENIX AND THIS
STILL LOOKS REASONABLE. TOUGH TO SAY HOW MUCH WILL DEVELOP EAST OF
PHOENIX. NOT MUCH IN THE WAY OF FORCING MECHANISMS OR SUBSTANTIAL
MOISTURE...BUT THERE IS DECENT POTENTIAL FOR MLCAPES AOA 1000 J/KG.
LEFT POPS IN THE 20-30 RANGE IN SOUTHERN GILA CO AS WELL.
THE WEEKEND STILL LOOKS TO BE QUITE ACTIVE ACROSS THE
REGION...SYNOPTIC SCALE MODEL AGREEMENT CONTINUES FOR AT LEAST THE
3RD OR 4TH DAY IN A ROW. ALL MODELS SUGGEST A SUBSTANTIAL INCREASE
IN MOISTURE ON SATURDAY WITH MIXING RATIOS CLIMBING INTO THE 10-12
G/KG RANGE...POSSIBLY TOPPING OUT ABOVE 14 G/KG. PWATS OF 2.0-2.2
INCHES WILL BE COMMON ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA THIS WEEKEND WITH SLIGHTLY LOWER VALUES TO THE EAST. THERE
ARENT ANY OBVIOUS TROUGHS DEPICTED IN THE FLOW DURING THE DAY ON
SATURDAY...BUT MID LEVEL SPEED CONVERGENCE BEGINS TO TAKE SHAPE LATE
SATURDAY NIGHT INTO SUNDAY MORNING. I REFINED POPS SLIGHTLY TO SHOW
THE HIGHEST VALUES FROM 00Z SUNDAY THROUGH 00Z MONDAY...CERTAINLY A
PRETTY LONG BROAD-BRUSHED PERIOD...BUT ONCE STORMS DEVELOP THEY
SHOULD HAVE NO PROBLEM MAINTAINING THEMSELVES ACROSS THE ENTIRE
REGION. POPS CWA-WIDE HAVE BEEN INCREASED INTO THE 60-80 PERCENT
RANGE. WOULD LIKE TO PLACE FURTHER TEMPORAL REFINEMENT INTO THE
FORECAST BUT IT WILL BE TOUGH UNTIL STORMS ACTUALLY BEGIN DEVELOPING.
UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND CONSEQUENTLY I
THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM COVERAGE
MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT FRIDAY
WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL TEMPS
GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE GFS AND
EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES NEXT
WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY PER
GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN PLACE...TUESDAY
AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF THESE TROUGHS
ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO NEED TO BE
LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.
&&
.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...INCLUDING KPHX...KIWA...KSDL...KIPL...AND KBLH...
A WEATHER DISTURBANCE OVER WESTERN ARIZONA WILL KEEP CLOUDINESS...AT
OR ABOVE 12 KFT MSL...IN PLACE BETWEEN PHOENIX AND FAR SOUTHEAST
CALIFORNIA THROUGH THE MORNING BEFORE DECREASING THIS AFTERNOON.
SHOWERS WILL BE POSSIBLE IN THAT AREA WITH MORE ACTIVITY OVER
NORTHERN ARIZONA AND SOUTHERN NEVADA. ONCE AGAIN...OUTFLOW WINDS
FROM DISTANT STORMS WILL BE A DISTINCT POSSIBILITY LATER TODAY/THIS
EVENING. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS AT EACH OF
THE TAF SITES BUT LESS ACTIVITY IS ANTICIPATED OVER THE LOWER
COLORADO RIVER VALLEY AND THE IMPERIAL VALLEY THAN ON THURSDAY.
CONFIDENCE IN STORMS OCCURRING OVER ANY GIVEN TAF SITE TOO LOW TO
REFLECT IN THE TAFS AT THIS POINT. APART FROM THUNDERSTORMS...WINDS
WILL BE LIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
246 AM MST FRI AUG 23 2013
.SYNOPSIS...
A GRADUAL INCREASE IN PRECIPITATION CHANCES...AS WELL AS A DECREASE
IN TEMPERATURES...IS EXPECTED OVER THE NEXT SEVERAL DAYS AND INTO
THIS WEEKEND. INCREASED PRECIPITATION CHANCES WILL CONTINUE THROUGH
EARLY NEXT WEEK.
&&
.DISCUSSION...
EVENING STORM ACTIVITY HAS LARGELY QUIETED DOWN ACROSS THE FORECAST
AREA THIS MORNING...WITH MOST OF THE STORMS SHIFTING NORTHWARD
OVER NORTHWEST ARIZONA AS OF 09Z. UPPER LEVEL DIFLUENCE IN AN AREA
OF 50+KT 250MB WINDS APPEARS TO BE THE DRIVING FORCE FOR THESE
STORMS AND WV IMAGERY SUGGESTS THE STORMS SHOULD REMAIN CONFINED TO
THE HIGHER TERRAIN NORTH OF THE CWA. LATEST RUN OF THE HRRR MODEL
WANTS TO CONTINUE RE-DEVELOPING STORMS AS FAR SOUTH AT YUMA THIS
MORNING...BUT THE BOUNDARY LAYER IS NO LONGER SUPPORTIVE OF STORMS
SINCE LAST EVENINGS CONVECTION. IN THE VERY SHORT TERM I WILL
MAINTAIN A 10-20 POP ACROSS LA PAZ AND FAR NORTHWEST MARICOPA COUNTY
IN THE EVENT THESE STORMS BACK-BUILD TO THE SOUTH...OTHERWISE NOT
EXPECTING MUCH STORM ACTIVITY FOR THIS MORNING.
TOUGH FORECAST FOR THIS AFTERNOON...AS THE TWO MOST RECENT RUNS OF
THE SREF PAINT A NEARLY IDENTICAL AREA OF ENHANCED MLCAPES ACROSS
WESTERN AND SOUTHERN ARIZONA. MEANWHILE...SLIGHTLY DRIER THAN NORMAL
AIR REMAINS IN PLACE FROM CENTRAL NEW MEXICO TO THE MOUNTAINS OF
EASTERN ARIZONA. HARD TO ENVISION STORMS FORMING IN THE IDENTICAL
AREAS TWO DAYS IN A ROW...ESPECIALLY GIVEN LITTLE RECOVERY TIME FROM
THURSDAYS CONVECTIVE OVERTURNING OF THE BOUNDARY LAYER.
NONETHELESS...I THINK STORMS ARE POSSIBLE ACROSS PORTIONS OF LA
PAZ...YUMA...AND WESTERN MARICOPA COUNTIES. NAMDNG5 AND NMM BASED
WRF MODELS ARE THE MOST VIGOROUS WITH THIS AFTERNOONS CONVECTION IN
THESE AREAS WHILE ARW BASED MODELS ARE A BIT MORE RESERVED.
INHERITED FORECAST DEPICTED 20-30 POPS WEST OF PHOENIX AND THIS
STILL LOOKS REASONABLE. TOUGH TO SAY HOW MUCH WILL DEVELOP EAST OF
PHOENIX. NOT MUCH IN THE WAY OF FORCING MECHANISMS OR SUBSTANTIAL
MOISTURE...BUT THERE IS DECENT POTENTIAL FOR MLCAPES AOA 1000 J/KG.
LEFT POPS IN THE 20-30 RANGE IN SOUTHERN GILA CO AS WELL.
THE WEEKEND STILL LOOKS TO BE QUITE ACTIVE ACROSS THE
REGION...SYNOPTIC SCALE MODEL AGREEMENT CONTINUES FOR AT LEAST THE
3RD OR 4TH DAY IN A ROW. ALL MODELS SUGGEST A SUBSTANTIAL INCREASE
IN MOISTURE ON SATURDAY WITH MIXING RATIOS CLIMBING INTO THE 10-12
G/KG RANGE...POSSIBLY TOPPING OUT ABOVE 14 G/KG. PWATS OF 2.0-2.2
INCHES WILL BE COMMON ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA THIS WEEKEND WITH SLIGHTLY LOWER VALUES TO THE EAST. THERE
ARENT ANY OBVIOUS TROUGHS DEPICTED IN THE FLOW DURING THE DAY ON
SATURDAY...BUT MID LEVEL SPEED CONVERGENCE BEGINS TO TAKE SHAPE LATE
SATURDAY NIGHT INTO SUNDAY MORNING. I REFINED POPS SLIGHTLY TO SHOW
THE HIGHEST VALUES FROM 00Z SUNDAY THROUGH 00Z MONDAY...CERTAINLY A
PRETTY LONG BROAD-BRUSHED PERIOD...BUT ONCE STORMS DEVELOP THEY
SHOULD HAVE NO PROBLEM MAINTAINING THEMSELVES ACROSS THE ENTIRE
REGION. POPS CWA-WIDE HAVE BEEN INCREASED INTO THE 60-80 PERCENT
RANGE. WOULD LIKE TO PLACE FURTHER TEMPORAL REFINEMENT INTO THE
FORECAST BUT IT WILL BE TOUGH UNTIL STORMS ACTUALLY BEGIN DEVELOPING.
UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND CONSEQUENTLY I
THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM COVERAGE
MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT FRIDAY
WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL TEMPS
GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE GFS AND
EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES NEXT
WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY PER
GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN PLACE...TUESDAY
AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF THESE TROUGHS
ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO NEED TO BE
LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
THICKER MID/HIGH CLOUDS WILL PREVAIL THROUGH FRIDAY MORNING...WITH
PRIMARY AVIATION IMPACT BEING POTENTIAL WIND SHIFTS AND THE OUTSIDE
CHANCE OF SHRA/TSRA REACHING TERMINALS THROUGH FRIDAY MORNING.
OUTFLOW BOUNDARIES HAVE LARGELY DISSIPATED THIS EVENING...THOUGH AN
EVENTUAL EASTERLY DRAINAGE WIND SHOULD DEVELOP BY THE OVERNIGHT
HOURS. RENEWED SHRA/TSRA MAY BE POSSIBLE FRIDAY AFTERNOON THOUGH
CONFIDENCE IS TOO LOW TO INCLUDE ANY MENTION AT THIS TIME.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
OUTFLOW AND VCTS MAY CONTINUE TO AFFECT APPROACHES INTO KBLH BEFORE
MIDNIGHT...WITH ONLY SHIFTING WINDS AND RESIDUAL DUST AFFECTING
KIPL. A MORE GENERAL CALM IN WEATHER CONDITIONS SHOULD BE EXPECTED
THROUGH FRIDAY MORNING...THOUGH SFC WINDS MAY CONTINUE TO REMAIN
RATHER VARIABLE THROUGH THE PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MODELS CONTINUE TO DEPICT MOISTURE FROM TROPICAL ORIGINS MAKING ITS
WAY INTO THE DESERT SOUTHWEST THIS WEEKEND. THUS HUMIDITIES WILL
INCREASE SUBSTANTIALLY ALONG WITH PRECIPITATION CHANCES.
TEMPERATURES WILL DECREASE...TO WELL BELOW NORMAL BY SUNDAY...BEFORE
INCREASING TO NEAR NORMAL BY TUESDAY AND WEDNESDAY. STRONGER
SOUTHERLY WINDS ARE ALSO EXPECTED ON SATURDAY...MAINLY OVER
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...WITH LESS BREEZINESS
THEREAFTER EXCEPT FOR THUNDERSTORM DRIVEN WINDS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS
AVIATION...MO
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1013 AM MDT FRI AUG 23 2013
.UPDATE...WITH LINGERING CLOUD COVER...HAVE ADJUSTED MAX
TEMPERATURES DOWN A COUPLE DEGREES...MAINLY OVER THE DENVER METRO
AREA AND FOOTHILLS.
WATER VAPOR SATELLITE STILL SHOWING PLENTY OF MOISTURE ROTATING
AROUND THE STATE...HOWEVER PRECIPITABLE WATER VALUES OVER
NORTHEAST CO ARE DOWN 0.3 INCHES FROM YESTERDAY AT THE SAME TIME.
MODELS STILL ADVERTISING DRIER AIR MOVING NORTH FROM NEW
MEXICO...HOWEVER BELIEVE LAST NIGHTS/THIS MORNINGS MCS OVER THE
STATE MAY HAVE DELAYED IT A BIT. STILL EXPECTING DRIER AIR TO
BEGIN TO MOVE UP FROM THE SOUTH LATER TODAY WHICH WILL LIMIT
STORM ACTIVITY OVER THE PLAINS...MAINLY SOUTH OF I76. ENOUGH
INSTABILITY OVER THE MOUNTAINS AND OVER CHEYENNE RIDGE WILL ALLOW
SCATTERED STORMS TO ONCE AGAIN FORM TODAY.
&&
.AVIATION...LIGHT WINDS NEAR THE AIRPORT SHOULD BEGIN
TRANSITIONING TO BE OUT OF THE NORTHEAST AS SOUTHERLY WINDS OVER
THE EASTERN PLAINS CYCLONE INTO THE AREA. THERE WILL BE A CHANCE
FOR THUNDERSTORMS THIS AFTERNOON...MAINLY FROM 21-01Z. HEAVY RAIN
AND WIND GUSTS TO 40 KNOTS WILL BE POSSIBLE WITH THE STRONGER
STORMS. HIGH-RES MODELS POINTING TO THE HIGHER TERRAIN OF PARK AND
JEFFERSON COUNTIES WITH SLIGHTLY MORE COVERAGE EARLIER ON THEN
BRING IT NORTHEAST TOWARD THE METRO AREAS. THIS WOULD LIKELY TURN
WINDS BACK FROM THE SOUTH. DRIER AIR WILL MOVE INTO THE AREA
TONIGHT AND BRING CLEARING SKIES.
&&
.PREV DISCUSSION... /ISSUED 338 AM MDT FRI AUG 23 2013/
SHORT TERM...SOUTHWEST FLOW ALOFT WILL PREVAIL AS THE UPPER LEVEL
HIGH SHIFTS EASTWARD TODAY. A LOW PRESSURE SYSTEM WILL FORM OVER
SOUTHERN ALBERTA DURING THE DAY AND A LOW PRESSURE TROUGH WILL
EXTEND SOUTHWARD ALONG THE LEE SIDE OF THE ROCKIES AND INTO
COLORADO. THIS WILL PRODUCE SOUTHERLY WINDS OVER EASTERN COLORADO.
DRIER OVER NEW MEXICO WILL BE PULLED NORTHWARD THROUGH THE DAY.
THE LATEST RAP SHOWS THE AIRMASS WILL STAY MOIST TODAY WITH
PRECIPITABLE WATER VALUES OF AN INCH TO 1.25 AND CAPES OF 1000 TO
1500 J/KG. THIS WOULD SUPPORT ANOTHER ROUND OF STRONG THUNDERSTORMS.
THE NAM AND GFS HAS PRECIPITABLE WATER VALUES OF 0.75 TO ONE INCH
WITH CAPES LESS THAN 700 J/KG. WHAT ACTUALLY HAPPENS WILL PROBABLY
BE SOMEWHERE IN BETWEEN THESE SOLUTIONS. WILL HAVE THE HIGHEST POPS
OVER THE MOUNTAINS AND ACROSS THE NORTHERN ZONES. ALL THE MODELS
HAVE SOME DRYING OVER THE SOUTHEAST ZONES AND IT SPREADS NORTH
DURING THE EVENING...THUS WILL HAVE THE LOWEST POPS HERE. EXPECT THE
CONVECTION TO END DURING THE EVENING HOURS AS DRIER AIR MOVES INTO
THE AREA.
TEMPERATURES WILL BE A FEW DEGREES WARMER TODAY. CLEARING SKIES THIS
MORNING AND EARLY AFTERNOON SHOULD ALLOW ENOUGH SUN TO PUSH HIGHS IN
THE UPPER 80S AND PERHAPS LOWER 90S. AS DRIER MOVES INTO THE AREA
TONIGHT...TEMPERATURES WILL FALL INTO THE 50S.
LONG TERM...MODELS SHOW THE UPPER RIDGE CENTERED OVER CENTRAL
KANSAS SATURDAY MORNING. IT MOVES INTO EASTERN KANSAS BY SUNDAY
NIGHT. THE FLOW ALOFT STAYS SOUTHWESTERLY OVER THE FORECAST AREA
ALL FOUR PERIODS. THE QG VERTICAL VELOCITY FIELD KEEP BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA THROUGH THE PERIOD. THE
BOUNDARY LAYER FLOW IS PROGGED TO BE PRETTY MUCH NORMAL DIURNAL
PATTERNS THROUGH SUNDAY NIGHT. FOR MOISTURE...MODELS SHOW A FAIR
AMOUNTS LATE DAY SATURDAY AND LATE DAY SUNDAY...BUT IT IS IN THE
MID AND UPPER LEVELS. THE BOUNDARY LAYER DEW POINT VALUES ARE
PROGGED IN THE 40S TO LOWER 50S F FOR THE PLAINS LATE DAY
SATURDAY...AND A TAD HIGHER LATE DAY SUNDAY. PRECIPITABLE WATER
VALUES ARE IN THE 0.65 TO 1.10 INCH RANGE OVER THE PLAINS SATURDAY
THROUGH SUNDAY NIGHT. THE HIGHEST VALUES ARE OUT EAST. THE CAPE IS
PRETTY LOW FOR LATE DAY SATURDAY...WITH THE HIGHEST VALUES OVER
THE FOOTHILLS. THEY GET UP 750 J/KG AT BEST THERE...WITH VALUES
OVER THE PLAINS FROM 100-500 J/KG. THERE IS EVEN LESS CAPE LATE
DAY SUNDAY FOR ALL AREAS. MEASURABLE RAINFALL IS PRETTY SPARSE ON
THE QPF FIELDS. THERE IS SOME LATE DAY SATURDAY OVER THE WESTERN
HALF OF THE CWA...THEN A TAD BIT LESS LATE DAY SUNDAY. FOR
POPS...20-30%S IN THE MOUNTAINS SHOULD DO FOR THE LATE DAYS AND
0-10%S OVER THE PLAINS. FOR TEMPERATURES...SATURDAY`S HIGHS ARE
1-2 C WARMER THAN TODAY`S EXPECTED HIGHS. SUNDAY`S ARE CLOSE TO
SATURDAY`S. FOR THE LATER DAYS...MONDAY THROUGH THURSDAY...MODELS
KEEP THE UPPER RIDGE CENTERED OVER KANSAS ALL FOUR DAYS. THE
SOUTHWESTERLY FLOW ALOFT STAYS AROUND FOR THE CWA AS WELL...BUT
MOISTURE IS SPARSE. TEMPERATURES LOOK TO STAY A BIT ABOVE SEASONAL
NORMALS.
AVIATION...SLIGHT CHANCE FOR PATCHY FOG AND LOW CLOUDS THIS
MORNING...NOT ENOUGH OF A CHANCE TO MENTION IN THE TAFS. THERE WILL
BE A CHANCE FOR THUNDERSTORMS THIS AFTERNOON...MAINLY FROM 20-01Z.
HEAVY RAIN AND WIND GUSTS TO 40 KNOTS WILL BE POSSIBLE WITH THE
STRONGER STORMS. DRIER AIR WILL MOVE INTO THE AREA TONIGHT AND BRING
CLEARING SKIES. SOUTHERLY WINDS ARE EXPECTED FOR MOST OF THE DAY.
HYDROLOGY...ANOTHER ROUND OF THUNDERSTORMS WILL FORM OVER THE
HIGHER TERRAIN AND SPREAD EASTWARD. HEAVY RAIN WILL AGAIN BE
POSSIBLE WITH THE STORMS WITH 1 INCH IN 15 TO 20 MINUTES OCCURRING.
FLASHING FLOODING COULD OCCUR IF A STRONG STORM FORMS OVER THE BURN
AREAS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MEIER
LONG TERM....RJK
UPDATE/AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
338 AM MDT FRI AUG 23 2013
.SHORT TERM...SOUTHWEST FLOW ALOFT WILL PREVAIL AS THE UPPER LEVEL
HIGH SHIFTS EASTWARD TODAY. A LOW PRESSURE SYSTEM WILL FORM OVER
SOUTHERN ALBERTA DURING THE DAY AND A LOW PRESSURE TROUGH WILL
EXTEND SOUTHWARD ALONG THE LEE SIDE OF THE ROCKIES AND INTO
COLORADO. THIS WILL PRODUCE SOUTHERLY WINDS OVER EASTERN COLORADO.
DRIER OVER NEW MEXICO WILL BE PULLED NORTHWARD THROUGH THE DAY.
THE LATEST RAP SHOWS THE AIRMASS WILL STAY MOIST TODAY WITH
PRECIPITABLE WATER VALUES OF AN INCH TO 1.25 AND CAPES OF 1000 TO
1500 J/KG. THIS WOULD SUPPORT ANOTHER ROUND OF STRONG THUNDERSTORMS.
THE NAM AND GFS HAS PRECIPITABLE WATER VALUES OF 0.75 TO ONE INCH
WITH CAPES LESS THAN 700 J/KG. WHAT ACTUALLY HAPPENS WILL PROBABLY
BE SOMEWHERE IN BETWEEN THESE SOLUTIONS. WILL HAVE THE HIGHEST POPS
OVER THE MOUNTAINS AND ACROSS THE NORTHERN ZONES. ALL THE MODELS
HAVE SOME DRYING OVER THE SOUTHEAST ZONES AND IT SPREADS NORTH
DURING THE EVENING...THUS WILL HAVE THE LOWEST POPS HERE. EXPECT THE
CONVECTION TO END DURING THE EVENING HOURS AS DRIER AIR MOVES INTO
THE AREA.
TEMPERATURES WILL BE A FEW DEGREES WARMER TODAY. CLEARING SKIES THIS
MORNING AND EARLY AFTERNOON SHOULD ALLOW ENOUGH SUN TO PUSH HIGHS IN
THE UPPER 80S AND PERHAPS LOWER 90S. AS DRIER MOVES INTO THE AREA
TONIGHT...TEMPERATURES WILL FALL INTO THE 50S.
.LONG TERM...MODELS SHOW THE UPPER RIDGE CENTERED OVER CENTRAL
KANSAS SATURDAY MORNING. IT MOVES INTO EASTERN KANSAS BY SUNDAY
NIGHT. THE FLOW ALOFT STAYS SOUTHWESTERLY OVER THE FORECAST AREA
ALL FOUR PERIODS. THE QG VERTICAL VELOCITY FIELD KEEP BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA THROUGH THE PERIOD. THE
BOUNDARY LAYER FLOW IS PROGGED TO BE PRETTY MUCH NORMAL DIURNAL
PATTERNS THROUGH SUNDAY NIGHT. FOR MOISTURE...MODELS SHOW A FAIR
AMOUNTS LATE DAY SATURDAY AND LATE DAY SUNDAY...BUT IT IS IN THE
MID AND UPPER LEVELS. THE BOUNDARY LAYER DEW POINT VALUES ARE
PROGGED IN THE 40S TO LOWER 50S F FOR THE PLAINS LATE DAY
SATURDAY...AND A TAD HIGHER LATE DAY SUNDAY. PRECIPITABLE WATER
VALUES ARE IN THE 0.65 TO 1.10 INCH RANGE OVER THE PLAINS SATURDAY
THROUGH SUNDAY NIGHT. THE HIGHEST VALUES ARE OUT EAST. THE CAPE IS
PRETTY LOW FOR LATE DAY SATURDAY...WITH THE HIGHEST VALUES OVER
THE FOOTHILLS. THEY GET UP 750 J/KG AT BEST THERE...WITH VALUES
OVER THE PLAINS FROM 100-500 J/KG. THERE IS EVEN LESS CAPE LATE
DAY SUNDAY FOR ALL AREAS. MEASURABLE RAINFALL IS PRETTY SPARSE ON
THE QPF FIELDS. THERE IS SOME LATE DAY SATURDAY OVER THE WESTERN
HALF OF THE CWA...THEN A TAD BIT LESS LATE DAY SUNDAY. FOR
POPS...20-30%S IN THE MOUNTAINS SHOULD DO FOR THE LATE DAYS AND
0-10%S OVER THE PLAINS. FOR TEMPERATURES...SATURDAY`S HIGHS ARE
1-2 C WARMER THAN TODAY`S EXPECTED HIGHS. SUNDAY`S ARE CLOSE TO
SATURDAY`S. FOR THE LATER DAYS...MONDAY THROUGH THURSDAY...MODELS
KEEP THE UPPER RIDGE CENTERED OVER KANSAS ALL FOUR DAYS. THE
SOUTHWESTERLY FLOW ALOFT STAYS AROUND FOR THE CWA AS WELL...BUT
MOISTURE IS SPARSE. TEMPERATURES LOOK TO STAY A BIT ABOVE SEASONAL
NORMALS.
&&
.AVIATION...SLIGHT CHANCE FOR PATCHY FOG AND LOW CLOUDS THIS
MORNING...NOT ENOUGH OF A CHANCE TO MENTION IN THE TAFS. THERE WILL
BE A CHANCE FOR THUNDERSTORMS THIS AFTERNOON...MAINLY FROM 20-01Z.
HEAVY RAIN AND WIND GUSTS TO 40 KNOTS WILL BE POSSIBLE WITH THE
STRONGER STORMS. DRIER AIR WILL MOVE INTO THE AREA TONIGHT AND BRING
CLEARING SKIES. SOUTHERLY WINDS ARE EXPECTED FOR MOST OF THE DAY.
&&
.HYDROLOGY...ANOTHER ROUND OF THUNDERSTORMS WILL FORM OVER THE
HIGHER TERRAIN AND SPREAD EASTWARD. HEAVY RAIN WILL AGAIN BE
POSSIBLE WITH THE STORMS WITH 1 INCH IN 15 TO 20 MINUTES OCCURRING.
FLASHING FLOODING COULD OCCUR IF A STRONG STORM FORMS OVER THE BURN
AREAS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MEIER
LONG TERM....RJK
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS ALBANY NY
421 PM EDT FRI AUG 23 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION
INTO THE NORTHEAST THROUGH SATURDAY...WITH A NORTHERLY FLOW
BRINGING COOLER TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS. THE
SURFACE ANTICYCLONE WILL DRIFT EAST OF NEW JERSEY ON SUNDAY WITH
CONTINUED FAIR WEATHER BUT WITH A SOUTHWEST FLOW AND SLIGHTLY
WARMER TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 415 PM EDT...PARTLY TO MOSTLY SUNNY SKIES PREVAIL ACROSS THE
REGION...WITH MOST OF THE CLOUDS CONFINED TO HIGHER TERRAIN WEST
AND EAST OF THE HUDSON RIVER VALLEY.
THESE CLOUDS SHOULD GRADUALLY DISSIPATE AROUND...OR JUST AFTER
SUNSET...LEAVING MOSTLY CLEAR TO CLEAR SKIES FOR THE OVERNIGHT
HOURS. THE LATEST RUC13 SUGGESTS A SECONDARY SURGE OF LOW
LEVEL...DRY AIR ADVECTING SOUTHWARD EARLY TONIGHT. THIS MAY ACT TO
KEEP THE BOUNDARY LAYER SOMEWHAT MIXED...PARTICULARLY IN THE
HUDSON VALLEY REGION...WITH A N/NE WIND PERSISTING WELL INTO THE
OVERNIGHT HOURS...WHICH MAY PRECLUDE FOG FORMATION AND ALSO VERY
COOL TEMPS FROM OCCURRING. THEREFORE...HAVE KEPT OUT MENTION OF
PATCHY FOG...AND HAVE INDICATED MIN TEMPS IN THE MID 40S TO LOWER
50S IN MOST AREAS...WITH SOME LOWER 40S POSSIBLE ACROSS PORTIONS
OF THE WESTERN ADIRONDACKS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
SAT-SUN...HIGH PRESSURE SHOULD PROVIDE GENERALLY CLEAR/SUNNY SKIES
FOR SAT...WITH JUST OCCASIONAL PASSING HIGH CLOUDS POSSIBLE LATE
SAT NT INTO SUNDAY. MIXING DEPTHS MAY BE SOMEWHAT SHALLOW FOR
SAT...COMPARED TO RECENT DAYS...GENERALLY UP TO BETWEEN 900 AND
875 MB. THIS SHOULD ALLOW FOR MAX TEMPS TO REACH 75-80 IN MOST
VALLEY AREAS...AND UPPER 60S TO LOWER/MID 70S ACROSS HIGHER
ELEVATIONS. FOR SAT NT/SUN AM...MIN TEMPS COULD BE A BIT COOLER
THAN TONIGHT...ESP SHOULD ANY HIGH CLOUDS HOLD OFF OR REMAIN VERY
THIN. HOWEVER...WITH LESS MIXING AND WIND COMPARED TO
TONIGHT...THE POTENTIAL FOR AT LEAST PATCHY GROUND FOG WILL BE
GREATER...WHICH COULD KEEP AREAS IMMEDIATELY ADJACENT TO BODIES OF
WATER A BIT WARMER. HAVE GENERALLY SIDED A BIT CLOSER TO THE
COOLER MAV MOS IN MOST AREAS...WITH MIN TEMPS FALLING INTO THE MID
40S TO LOWER 50S IN MOST VALLEY AREAS...AND MAINLY LOWER/MID 40S
ACROSS HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND...AND THE
EASTERN CATSKILLS/WESTERN ADIRONDACKS. ACROSS SOME SHELTERED
PORTIONS OF THE SOUTHERN ADIRONDACKS...AND EASTERN
CATSKILLS...SOME UPPER 30S COULD EVEN OCCUR BY DAYBREAK SUNDAY.
AFTER THE CHILLY START...EXPECT SLIGHTLY DEEPER MIXING WITH A
DEVELOPING SOUTHWEST LOW LEVEL FLOW TO ALLOW FOR WARMER MAX TEMPS
ON SUNDAY...WITH UPPER 70S TO LOWER 80S IN MOST VALLEYS...AND
70-75 FOR HIGHER ELEVATIONS.
SUN NT-MON NT...FORECAST UNCERTAINTY INCREASES DURING THIS PERIOD
AS LOW/MID LEVEL WARM ADVECTION STRENGTHENS LATE SUN NT INTO
MONDAY...IN RESPONSE TO A POTENTIAL MID LEVEL DISTURBANCE
APPROACHING FROM THE GREAT LAKES REGION. THIS PATTERN SHOULD ALLOW
FOR INCREASING CLOUDS LATE SUN NT...WITH THE POSSIBILITY OF
SHOWERS FOR MON-MON NT. SOME THUNDERSTORMS COULD OCCUR AS
WELL...ESP LATE MON INTO MON NT AS ELEVATED INSTABILITY DEVELOPS.
EXPECT OVERNIGHT MIN TEMPS TO BE WARMER...WITH MAINLY LOWER/MID
60S FOR VALLEY AREAS...AND 55-60 ACROSS HIGHER ELEVATIONS. MON MAX
TEMPS SHOULD REACH THE MID 70S TO LOWER 80S...ALTHOUGH SHOULD
WIDESPREAD SHOWERS OR A PERIOD OF STEADIER RAIN OCCUR...EVEN
COOLER MAX TEMPS COULD OCCUR.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A CONTINUOUS PATTERN OF DISTURBANCES THAT ARE POTENTIAL RIDGE
ROLLERS SHOULD FLOW FROM NORTHWEST TO SOUTHEAST ON THE NORTHEAST
SIDE OF A BROAD UPPER LEVEL HIGH PRESSURE...CENTERED OVER THE
CENTRAL PLAINS...WHICH WILL AFFECT OUR WEATHER FOR THE EXTENDED
PERIOD. CURRENT THINKING IS THAT THE 12Z MODELS ARE A BIT
DISORGANIZED DUE TO THE EXTENT OF THE RIDGE ITSELF THAT WILL DICTATE
THE SYNOPTIC TRACK OF THESE LOW PRESSURE IMPULSES AS THEY MOVE ON
THE OUTSKIRTS OF THE HIGH PRESSURE SYSTEM. CHANCE POPS WILL BE
THROUGHOUT THE EXTENDED PERIOD TO INCORPORATE THE DIFFERENT
PROBABILITY BLENDS IN THE FORECAST. OUR BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH AN UPPER LEVEL POSITIVE TILTED TROUGH
WITH A POSSIBLE DEVELOPING SURFACE LOW PRESSURE NEAR THE US/CANADA
BORDER WILL BE ON WEDNESDAY NIGHT INTO THURSDAY MORNING. THE GENERAL
CONSENSUS AS OF NOW SHOWS CLEARING IN THE AREA LATE THURSDAY MORNING
AS THE RIDGE FROM THE CENTRAL PLAINS SHIFTS EAST AND HAS MORE OF AN
INFLUENCE ON OUR WEATHER PATTERN...GIVING TRANQUIL CONDITIONS FOR
THE DAY ON FRIDAY. A WARM UP TO ABOVE AVERAGE TEMPERATURES GOING
FROM FRIDAY INTO NEXT WEEKEND IS POSSIBLE AS THE RIDGE CONTINUES TO
MOVE EAST NORTHEAST INTO OUR REGION.
HIGH TEMPERATURES THROUGHOUT THE EXTENDED PERIOD WILL RANGE FROM
THE MID AND UPPER 70S IN THE HIGH TERRAIN TO LOWER 80S IN VALLEY
LOCATIONS. LOW TEMPERATURES WILL RANGE FROM THE UPPER 50S TO MID 60S
FOR THE ENTIRE REGION.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE MAJORITY OF THE UPCOMING TAF PERIOD WILL BE VFR. SOME MORNING
FOG IS POSSIBLE AT KGFL...WHERE IT COULD BE LOCALLY DENSE
RESULTING IN LIFR CONDITIONS...AND AT KPSF WHERE MVFR IS MORE
LIKELY. A LIGHT NORTHERLY FLOW AND DRY AIR ADVECTION WILL RESULT
IN MODERATE MIXING OVERNIGHT SO FOG IS NOT EXPECTED AT KALB AND KPOU.
NORTHWEST TO NORTH WINDS AROUND 10 KNOTS TODAY WILL DIMINISH THIS
EVENING BECOMING CALM OVERNIGHT. LIGHT NORTHERLY WINDS ARE AGAIN
EXPECTED ON SATURDAY.
OUTLOOK...
SATURDAY NIGHT: NO OPERATIONAL IMPACT. PATCHY FG.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. ISOLATED SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
&&
.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE ANTICIPATED THE NEXT FEW DAYS. HIGH
PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION AND
SOUTHEASTERN CANADA ACROSS THE NORTHEAST TODAY INTO
SATURDAY...WITH COOLER TEMPERATURES AND COMFORTABLE HUMIDITY
LEVELS. THE SURFACE ANTICYCLONE WILL DRIFT SOUTH AND EAST OF THE
NORTHEAST ON SUNDAY WITH TEMPERATURES MODERATING SLIGHTLY ABOVE
NORMAL WITH CONTINUED FAIR WEATHER.
RELATIVE HUMIDITY VALUES WILL RECOVER TO 90 TO 100 PERCENT
TONIGHT WITH SOME DEW FORMATION POSSIBLE. THE RH VALUES WILL FALL
TO 30 TO 45 PERCENT SATURDAY AFTERNOON...THEN RECOVER TO 90-100
PERCENT FOR SAT NT WITH WIDESPREAD DEW FORMATION LIKELY.
NORTH TO NORTHEAST WINDS AT 10-15 MPH WILL DECREASE TO 5-10 MPH
OVERNIGHT. WINDS WILL BE NORTHEAST TO EAST AT 5-15 MPH
SATURDAY...THEN BECOME LIGHT AND VARIABLE FOR SAT NT.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH THE WEEKEND. THE WEATHER BECOMES
MORE UNSETTLED SUNDAY NIGHT INTO TUESDAY WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS AS A LOW PRESSURE SYSTEM AND ITS
ASSOCIATED FRONTAL BOUNDARIES APPROACHES FROM THE GREAT LAKES
REGION. PRECIPITATION AMOUNTS WILL BE HIGHLY VARIABLE DEPENDING ON
ANY CONVECTION.
OVERALL FOR THE NEXT 5 DAYS...NO WIDESPREAD HYDRO PROBLEMS ARE
EXPECTED. RIVER FLOWS...AND RESERVOIR LEVELS CONTINUE AT NORMAL TO
SLIGHTLY BELOW NORMAL LEVELS FOR LATE AUGUST.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...LFM
AVIATION...SND
FIRE WEATHER...KL/WASULA
HYDROLOGY...KL/WASULA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
230 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL APPROACH FROM THE EAST THIS
EVENING...AND PASS TO THE SOUTH TONIGHT. HIGH PRESSURE WILL THEN
BUILD IN THIS WEEKEND...AND SETTLE TO THE SOUTH EARLY NEXT WEEK.
MULTIPLE LOWS WILL IMPACT THE NORTHEAST NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH CLOUD DEBRIS FROM MID ATLANTIC MCS HAS DRIFTED IN...MAKING
FOR WITH A PTCLDY AFTERNOON AND EVENING. MEANWHILE...SUBTLE
FRONTAL BOUNDARY/CONVERGENCE ZONE IS MOVING IN FROM THE EAST...
MARKED ATTM BY CLOUD LINE CUTTING NE-SW ACROSS RHODE ISLAND...
WITH NE FLOW ON THE COOL EAST SIDE OF THE BOUNDARY. THE BOUNDARY
SHOULD GRADUALLY DRIFT SW INTO THE AREA...WITH HRRR SHOWING
POTENTIAL FOR A FEW SHOWERS OVER FAR ERN CT/LONG ISLAND. HRRR IS
USUALLY TOO QUICK TO INITIATE CONVECTION SO INTRODUCED SLIGHT
CHANCE POP FOR THESE AREAS INTO THIS EVENING RATHER THAN LATE
AFTERNOON. BOUNDARY COULD SPARK A FEW ADDITIONAL SHOWERS
TONIGHT...BUT THINK THESE WILL BE MAINLY OVER THE OCEAN AND IN
TANDEM WITH A MID LEVEL SHORTWAVE TROUGH MOVING OHD TONIGHT.
OTHERWISE...SKIES SHOULD BECOME MOSTLY CLEAR WITH DIMINISHING N-NE
WINDS FOR MOST OF THE NIGHT...THEN PICKING UP A LITTLE TOWARD
DAYBREAK ALONG THE COAST AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH PRESSURE BUILDING FROM THE NW AND LOW PRESSURE FORMING ALONG
A FRONTAL ZONE SE OF CAPE COD. LOWS TONIGHT ARE A GUIDANCE
BLEND...WITH 50S FOR INLAND SECTIONS...COASTAL SE CT AND THE LONG
ISLAND PINE BARRENS...AND 60S ELSEWHERE.
&&
.SHORT TERM /SATURDAY INTO SATURDAY NIGHT/...
SUNNY AND MILD ON SAT AS NORTHERLY WINDS CONTINUE TO USHER IN
SLIGHTLY COOLER AND DRIER AIR....WITH HIGHS 1-2 DEG EITHER SIDE
OF 80. AS THE HIGH BUILDS TO THE NORTH...FLOW ALONG THE COAST
SHOULD TURN E-SE IN THE AFTERNOON.
COOLER SAT NIGHT WITH MOCLEAR SKIES AND LIGHT WINDS. LOWS WILL BE
60-65 IN NYC METRO...IN THE 50S MOST ELSEWHERE...AND 45-50 IN THE
INTERIOR VALLEYS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A GENERALLY QUIET BEGINNING TO THE COMING WEEK...WITH INCREASING
CHANCES OF ACTIVITY THROUGH THE WEEK WITH MULTIPLE SYSTEMS PASSING
THROUGH. UPPER LEVEL PATTERN REMAINS FAIRLY CONSISTENT AS RIDGING
SETS UP OVER THE CENTRAL US...KEEPING THE NORTHEAST REGION ON THE
OUTER PERIPHERY OF THE RIDGE AND IN LINE FOR THE PASSING OF
MULTIPLE SHORTWAVES.
SUNDAY QUIET WITH THE CENTER OF THE SURFACE HIGH SITTING OHD AND
SUBSIDENCE ALOFT PRODUCING MOSTLY CLEAR/SUNNY SKIES. INCREASING
CLOUD COVERAGE SUNDAY NIGHT INTO MONDAY AS THE FIRST OF MANY
SHORTWAVES ROUNDS THE RIDGE. BEGAN INTRODUCING POPS BY LATE AFTN
MONDAY AS THE SURFACE HIGH SLIPS TO THE SOUTH AHEAD OF AN
APPROACHING FRONTAL SYSTEM AND MORE PROMINENT SHORTWAVES ROUND THE
RIDGE. SOME MODEL DIVERGENCE ON THE HANDLING OF THE LOW PRESSURE
SYSTEM...HOW STRONG AND HOW QUICKLY IT PROGRESSES THROUGH AND
WHETHER A SECONDARY LOW FORMS ALONG THE FRONT BY THURS. THE 00Z
GFS/CMC HAVE A MORE PRONOUNCED LOW AND THE 00Z ECMWF A BIT QUICKER
WITH THE INTRODUCTION OF PCPN MONDAY AS WELL AS LINGERING IT
LONGER INTO MID WEEK WITH THE DEVELOPMENT OF THE SECOND LOW AND
LINGERING IT OFF THE NE COAST. WITH SUCH DIFFERENCES IN THE MODELS
AT THIS TIME...WILL MAINTAIN LOWER END CHC POPS MON NIGHT-
WED...WITH DRYING CONDITIONS FOR NOW FOR THE END OF THE WEEK IN
THE WAKE OF A PASSING COLD FRONT AND SUBSIDENCE ATTEMPTING TO
BUILD IN ALOFT. ANY ACTIVITY THAT DOES DEVELOP EARLIER IN THE WEEK
AT THE MOMENT LOOKS TO BE MORE SCATTERED IN NATURE.
AFTER A WEEKEND OF NEAR NORMAL TEMPS...WAA WILL LEAD TO INCREASED
TEMPS AND DEWPTS...RESULTING IN MORE HUMID CONDITIONS AND ABOVE
NORMAL TEMPS. THIS WILL AID IN INCREASING THE INSTABILITY AS
WELL...SO WILL KEEP MENTION OF THUNDER IN FOR THE FIRST HALF OF
THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
HIGH PRESSURE BUILDS INTO THE TERMINALS THROUGH SATURDAY.
VFR. A BRIEF SHOWER IS POSSIBLE 05Z TO 10Z IN THE VICINITY OF KJFK
AND KISP.
NORTHERLY WIND GRADUALLY BECOMES MORE NORTH TO NORTHEAST...020 TO
030...THIS AFTERNOON WITH ANY GUSTS SUBSIDING BY 22Z. WIND REMAINS
NORTHEAST OVERNIGHT AND INTO SATURDAY AFTERNOON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: OCCASIONAL GUSTS UP TO 20 KT POSSIBLE THROUGH
21Z.
KJFK FCSTER COMMENTS: OCCASIONAL GUSTS UP TO 20 KT POSSIBLE THROUGH
21Z.
KLGA FCSTER COMMENTS: GUSTS TO AROUND 20 KT CONTINUE THROUGH 21Z. AN
OCCASIONAL GUSTS TO 23Z WILL BE POSSIBLE.
KTEB FCSTER COMMENTS: AN OCCASIONAL GUST TO AROUND 15 KT WILL BE
POSSIBLE THROUGH 21Z.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...
.SATURDAY AFTERNOON-MONDAY...VFR.
.MONDAY NIGHT-WEDNESDAY...SUB-VFR POSSIBLE IN SHRA/TSRA WITH LOW
PRESSURE MOVING THROUGH THE AREA.
&&
.MARINE...
N FLOW SHOULD TURN E-NE THIS EVENING AS A WEAK FRONTAL BOUNDARY
MOVES IN FROM THE EAST...AND THEN MORE NE LATE TONIGHT AS THE
PRESSURE GRADIENT TIGHTENS BETWEEN HIGH PRESSURE BUILDING FROM
THE NW AND LOW PRESSURE FORMING ALONG A FRONTAL ZONE SE OF CAPE
COD. WIND GUSTS AND OCEAN SEAS SHOULD APPROACH BUT FALL SHY OF SCA
CRITERIA OF 25 KT AND 5 FT LATE TONIGHT INTO EARLY SAT MORNING.
OTHERWISE...QUIET THROUGH SAT NIGHT AS HIGH PRESSURE BUILDS IN.
A WEAK PRESSURE GRADIENT RESULTING FROM HIGH PRESSURE KEEPS SUB-
SCA CONDITIONS ON ALL WATERS TO END THE WEEKEND AND BEGIN THE
COMING WEEK. POSSIBLE 5 FT SEAS ON THE OCEAN WATERS BY TUESDAY
WITH PERSISTENT AND INCREASING SW FLOW AHEAD OF AN APPROACHING
FRONTAL SYSTEM. SEAS ARE EXPECTED TO SUBSIDE BY WED AND SHOULD
REMIND SUB-SCA THEN FOR THE REST OF THE WEEK. THUNDERSTORMS IN THE
FIRST HALF OF THE WEEK MAY BRING SOME STRONGER GUSTS...BUT
OTHERWISE WINDS SHOULD REMAIN BELOW 25 KT FOR THE PERIOD.
&&
.HYDROLOGY...
THERE IS SOME HEAVY RAIN POTENTIAL FOR NEXT WEEK. IT IS STILL TOO
EARLY TO BE SPECIFIC ON EXACT TIMING/LOCATION.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD...THE NEW
YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 HAS BEEN
TEMPORARILY TAKEN OUT OF SERVICE WHILE A SOLUTION IS
BEING FORMULATED.
DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS RADIO PUBLIC WARNING
SYSTEM DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/MPS
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...SEARS
AVIATION...MET
MARINE...GOODMAN/MPS
HYDROLOGY...GOODMAN/MPS
EQUIPMENT...GOODMAN
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1008 AM EDT Fri Aug 23 2013
...LOCALLY HEAVY RAIN AND STORMY WEATHER EXPECTED LATER TODAY...
.NEAR TERM [Rest of Today]...
The large scale longwave pattern is highlighted by a broad ridge
over Cntrl Conus with high over OK, flanked by troughs along the
Pac and Atlc coasts (with base over N GA). Closer to home,
weakening TUTT moving Wwd across w/Cntrl gulf and high just off SE
FL coast. This places local area in a weakness between all these
systems. At surface, high pressure remains in place with ridge from
from high in Atlc east of N FL Wwd to high over FL Panhandle
creating ELY flow. Looking Nwd, frontal boundary extends across
Carolina and extreme Nrn GA. Looking SW, a tropical wave continues
to move Wwd across W/Cntrl gulf. A weak MCV was noted just south of
Pensacola moving Wwd with moist SELY flow in its wake. Latest radar
pix show a fair amount of marine convection moving Nwd.
During the rest of today, Ern mid/upper trough will dig Swd reaching
N FL by tonight. This will displace high Swd and allow front to dip
SWD. With digging trough and local area on back side of MCV,
PWATS will remain above 2 inches. HI RES models like HRRR have a
current good handle on weather which like yesterday shows marine
convection moving Nwd overland by midday and proceeding Nwd reaching
over Nrn tier counties during the mid-late aftn. The mean 1000-700mb
flow will light from the SE so storms that develop will be slow
movers with the potential for very heavy downpours. The combination
of the digging front, approaching surface front and seabreeze-
mesoscale interactions will favor strong to isold severe storms with
damaging wind gusts. Toward sundown, focus will shift towards I-75
corridor and the merging of Gulf and east coast seabreeze. The main
difference from yesterday is that lack of clouds will favor early
diurnal heating with a better destabilization and strong to severe
storms. This reflected in model soundings, i.e. RAP13 19Z TAE with
Cpae 3134 j/kg and 2.20 inch PWAT. Will go with 70-40% S-N POP
gradient. Max temps will once again be held below seasonal levels,
mid 80s south to near 90 NE GA counties.
&&
.SHORT TERM [Tonight through Sunday]...
A backdoor "cold front" will translate slowly southward along the GA
& Northeast FL coast this weekend, though any significant cooling
and/or drying will remain well to our northeast. With ample deep
layer moisture in place through the weekend, persistent, weak Q-G
forcing associated with this front will maintain above-average rain
chances across much of our forecast area, especially during the
daytime hours over land (and overnight & morning hours over the
coastal waters). The above-average cloud cover may help keep high
temperatures a few degrees below climo.
&&
.LONG TERM [Sunday Night through Thursday]...
The long term period begins a bit of unsettled with a stalled
frontal boundary across our southern CWA. Through the day on
Sunday and into Monday deep layer ridging builds over the Plains,
with surface high pressure advancing southwestward through the
southeast US. A significantly drier air mass gets advected around
the surface high pressure reducing PoPs around normal in our
southern zones, and below normal for our northern zones. Any
shower and thunderstorm activity through the period will primarily
be driven by the afternoon sea breeze.
&&
.AVIATION [Through 12Z Saturday]...
VFR conditions are expected into the aftn hours. Scattered to
numerous showers and thunderstorms are expected this afternoon
spreading from the coast rest of this mornnig inland through the
morning and into the afternoon. MVFR CIGS/VSBYS likely in any
stronger storms and heavier rain. Will go with VCTS transitioning
to TSRA ending during the eve from S-N. Then VFR returns until
after 07z-08z with MVFR VSBYS and possibly CIGS except for IFR
CIGS likely at VLD towards sunrise.
&&
.MARINE...
We are going on the assumption (backed by the agreement of the GFS
and ECMWF) that the broad, weak low pressure trough (currently in
the north central Gulf of Mexico) will not intensify significantly,
keeping our local pressure gradient fairly "loose". This means east
winds generally less than 15 KT and seas less than 4 feet.
&&
.FIRE WEATHER...
No fire weather concerns.
&&
.HYDROLOGY...
With Precip Water values continuing above average and Flash Flood
Guidance still below average, we still have to think about any
potential for flash flooding. Fortunately, the Convection Allowing
Models (CAM) consensus doesn`t forecast much in the way of
sustained, organized convection today. So although rainfall rates
could be very high (3-4 inches/hour), the expected lack of
organization makes issuing a watch unnecessary at this time. If
flooding occurs, it would most likely be limited to urban areas
and/or low-lying areas that already have standing water.
Several of our local rivers continued with high flows/stages,
mainly in the lower portions of the basins. Of these, the Chipola
River at Altha, Choctawhatchee River at Bruce, and Ochlockonee
River at Concord and Havana were at moderate flood stage or
higher. Please refer to our web page for details, under the "Rivers
& Lakes" tab.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 88 71 89 71 89 / 70 30 50 30 40
Panama City 85 75 87 76 86 / 70 40 50 30 40
Dothan 87 72 88 72 89 / 50 20 40 30 30
Albany 90 72 91 72 89 / 50 20 40 30 30
Valdosta 89 72 89 70 88 / 60 20 50 30 40
Cross City 88 73 88 72 88 / 70 30 50 30 40
Apalachicola 85 75 86 77 86 / 70 40 50 30 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM/Aviation/Marine...Block
SHORT TERM...Fournier
LONG TERM...Navarro/DVD
FIRE WEATHER...Barry
HYDROLOGY...Fournier
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
150 PM EDT FRI AUG 23 2013
.PREV DISCUSSION... /ISSUED 1128 AM EDT FRI AUG 23 2013/
UPDATE...
HAVE MADE SEVERAL MAINLY MINOR TWEAKS TO GRIDS THIS MORNING...
MAINLY TO UPDATE TRENDS. DID REDUCE POPS FOR THE MORNING AND EARLY
AFTERNOON HOURS BUT EXCEPT FOR SENDING THE NEW GRIDS TO THE WEB...
NO UPDATED PRODUCTS NECESSARY WITH THAT SINCE AFTERNOON POPS
REMAIN THE SAME. AS CONVECTION FIRES...MAY HAVE TO REEVALUATE
LOCATION OF HIGHEST POPS THROUGH THE AFTERNOON BUT FOR THE MOST
PART GRIDS LOOK GOOD. NO UPDATE PLANNED.
TDP
PREV DISCUSSION... /ISSUED 748 AM EDT FRI AUG 23 2013/
PREV DISCUSSION... /ISSUED 348 AM EDT FRI AUG 23 2013/
SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SOUTHEAST SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING
FROM THE EASTERN CAROLINAS THROUGH EXTREME SOUTH GEORGIA WITH WEAK
RIDGING ACROSS THE TENNESSEE VALLEY INTO NORTH GEORGIA. A STRONGER
FRONT IS NOTED TO THE NORTH AS HIGH PRESSURE MOVES INTO THE GREAT
LAKES REGION AND DRIVES FRONT INTO THE OHIO VALLEY AND PORTIONS OF
THE APPALACHIANS. ALTHOUGH NOT COMPLETELY DRY...WATER VAPOR
IMAGERY DOES SHOW SLOT OF DRIER AIR OVER NORTH GEORGIA WHICH ALONG
WITH A LACK OF MID LEVEL FORCING HAS ALLOWED FOR TRANQUIL
OVERNIGHT CONDITIONS. WILL NEED TO WATCH CLOSELY TOWARD DAYBREAK
AS NAM12 CONDENSATION PRESSURE DEFICIT ANALYSIS INDICATES A GOOD
CHANCE OF FOG AND LOW CIGS OVER PORTIONS OF NORTH GEORGIA
INCLUDING THE NORTHERN METRO AND A SEPARATE BATCH COMING UP FROM
THE SOUTH LATE. HAVE ADDED PATCHY FOG TO GRIDS TO COVER FOR NOW
BUT THIS COVERAGE OR INTENSITY MAY NEED TO BE INCREASED.
FOR TODAY...BASED SOLELY ON AVAILABLE MOISTURE AND UTILIZING PWAT
FORECAST...SOUTHERN SECTIONS SHOULD SEE THE BEST CHANCES THIS
AFTERNOON. HOWEVER...WRF AND HRRR AS WELL AS SOME OTHER SHORT TERM
MODELS POINT TO SECONDARY DEVELOPMENT LATE AS SHORTWAVE ENERGY
DIVES INTO THE NORTHERN SECTIONS. TRIED TO ACCOUNT FOR BOTH
PROJECTIONS WITH HIGHER POPS SOUTH AND NORTH WITH LOWER POPS IN
THE MIDDLE COVERING THE ATLANTA METRO. CAPES GENERALLY AROUND 2000
J/KG TO 3000 J/KG WILL BE POSSIBLE WHICH WILL BE SUFFICIENT TO
FUEL ISOLATED STRONG THUNDERSTORMS. DCAPE LOOKS TO REMAIN BELOW
1000 J/KG BUT ENOUGH PRECIPITATION LOADING WILL BE PRESENT TO
ALLOW FOR MICROBURST POTENTIAL. MORE STORM MOTION TODAY BY A
COUPLE OF KNOTS BUT FEEL BOUNDARY COLLISIONS ALONG WITH LOW FFG
VALUES COULD STILL LEAD TO ISOLATED FLASH FLOODING ACROSS THE AREA.
OHIO VALLEY HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST STATES WITH
RIDGING AND SUBTLE EDGE FEATURE THROUGH THE CAROLINAS AND GEORGIA.
ADDITIONAL DRY AIR SHOULD KEEP FOCUS OF HIGHEST POPS FOR THE
SOUTHERN SECTIONS...EXCEPT NORTHEAST MOUNTAINS WHERE NAMDNG5 SHOWS
ENHANCED DEVELOPMENT DURING THE AFTERNOON.
DEESE
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT IS FORECAST TO MOVE S OF THE AREA SATURDAY EVENING AS
SURFACE HIGH PRESSURE BUILDS ALONG THE EASTERN SEABOARD AND UPPER
LEVEL HIGH PRESSURE BUILDS OVER THE MID U.S. SHOWER AND THUNDERSTORM
CHANCES SHOULD BE HIGHLY DIURNAL SATURDAY NIGHT AND DIMINISH WITH THE
LOSS OF HEATING. SHOWER AND THUNDERSTORM CHANCES LOOK TO BE LIMITED
TO MAINLY CENTRAL GA ON SUNDAY DURING THE AFTERNOON AND EARLY
EVENING HOURS WHERE THE BEST INSTABILITY IS EXPECTED TO BE WITH THE
INFLUENCE OF DRIER AIR AND HIGH PRESSURE HAVING THE MOST AFFECT ON N
GA.
PRECIP CHANCES FOR MONDAY AND TUESDAY LOOK TO BE AS LOW AS WE HAVE
SEEN IN A LONG TIME WITH A GENERALLY DRIER AIRMASS OVER THE AREA AND
THE INFLUENCE OF HIGH PRESSURE. GFS IS MORE AGGRESSIVE WITH PRECIP
AMOUNTS AND CHANCES THAN THE EUROPEAN. WILL NEED TO WATCH THE NE
MOUNTAINS AND FAR S AS AREAS WHERE SMALL CHANCES COULD BE NEEDED.
GFS MORE AGGRESSIVE WITH MOISTURE RETURN ON WEDNESDAY THAN THE
EUROPEAN FROM THE NNW FLOW ALOFT. GUIDANCE FROM HPC FAVORING LOW
POPS FOR N AND PORTIONS OF CENTRAL GA. A SURFACE TROUGH DEVELOPS
ACROSS THE AREA ON THURSDAY AND AGAIN THE GFS IS MORE AGGRESSIVE WITH
THE MOISTURE THAN THE EUROPEAN IN THE NNW FLOW ALOFT. HPC GUIDANCE
FAVORING LOW POPS ACROSS THE ENTIRE AREA DUE TO THE UNCERTAINTY.
BOTH MODELS INDICATING INCREASED MOISTURE OVER THE AREA ON FRIDAY.
TEMPERATURES GENERALLY RUNNING NEAR TO AROUND 6 DEGREES BELOW NORMAL
DURING THIS PERIOD.
BDL
&&
.AVIATION...
18Z UPDATE...
VFR EVERYWHERE THIS AFTERNOON. HAVE KEPT FORMER PROB30 TIMING AND
JUST CHANGED TO TEMPO AT ATL...WILL MONITOR FOR OTHER SITES.
EXPECT MVFR FOG TO DEVELOP AGAIN IN THE MORNING WITH WIND SHIFT TO
NE AFTER 06Z. MAY SEE LOWER CONDITIONS AGAIN AT MCN LIKE THIS
MORNING. CLEARING AFTER 14Z. ADDED ANOTHER PROB30 FOR ATL SATURDAY
AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON AFTERNOON CONVECTION.
MEDIUM ON VSBY SATURDAY MORNING.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 73 84 67 / 40 30 30 20
ATLANTA 89 75 86 70 / 40 20 30 20
BLAIRSVILLE 86 67 81 65 / 50 20 30 10
CARTERSVILLE 90 72 87 69 / 30 20 20 20
COLUMBUS 90 77 88 72 / 50 30 30 20
GAINESVILLE 88 73 83 69 / 40 20 30 20
MACON 91 74 87 71 / 50 30 30 20
ROME 91 72 87 69 / 40 20 20 20
PEACHTREE CITY 88 72 85 69 / 40 20 30 20
VIDALIA 89 75 88 71 / 50 30 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1128 AM EDT FRI AUG 23 2013
.UPDATE...
HAVE MADE SEVERAL MAINLY MINOR TWEAKS TO GRIDS THIS MORNING...
MAINLY TO UPDATE TRENDS. DID REDUCE POPS FOR THE MORNING AND EARLY
AFTERNOON HOURS BUT EXCEPT FOR SENDING THE NEW GRIDS TO THE WEB...
NO UPDATED PRODUCTS NECESSARY WITH THAT SINCE AFTERNOON POPS
REMAIN THE SAME. AS CONVECTION FIRES...MAY HAVE TO REEVALUATE
LOCATION OF HIGHEST POPS THROUGH THE AFTERNOON BUT FOR THE MOST
PART GRIDS LOOK GOOD. NO UPDATE PLANNED.
TDP
&&
.PREV DISCUSSION... /ISSUED 748 AM EDT FRI AUG 23 2013/
PREV DISCUSSION... /ISSUED 348 AM EDT FRI AUG 23 2013/
SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SOUTHEAST SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING
FROM THE EASTERN CAROLINAS THROUGH EXTREME SOUTH GEORGIA WITH WEAK
RIDGING ACROSS THE TENNESSEE VALLEY INTO NORTH GEORGIA. A STRONGER
FRONT IS NOTED TO THE NORTH AS HIGH PRESSURE MOVES INTO THE GREAT
LAKES REGION AND DRIVES FRONT INTO THE OHIO VALLEY AND PORTIONS OF
THE APPALACHIANS. ALTHOUGH NOT COMPLETELY DRY...WATER VAPOR
IMAGERY DOES SHOW SLOT OF DRIER AIR OVER NORTH GEORGIA WHICH ALONG
WITH A LACK OF MID LEVEL FORCING HAS ALLOWED FOR TRANQUIL
OVERNIGHT CONDITIONS. WILL NEED TO WATCH CLOSELY TOWARD DAYBREAK
AS NAM12 CONDENSATION PRESSURE DEFICIT ANALYSIS INDICATES A GOOD
CHANCE OF FOG AND LOW CIGS OVER PORTIONS OF NORTH GEORGIA
INCLUDING THE NORTHERN METRO AND A SEPARATE BATCH COMING UP FROM
THE SOUTH LATE. HAVE ADDED PATCHY FOG TO GRIDS TO COVER FOR NOW
BUT THIS COVERAGE OR INTENSITY MAY NEED TO BE INCREASED.
FOR TODAY...BASED SOLELY ON AVAILABLE MOISTURE AND UTILIZING PWAT
FORECAST...SOUTHERN SECTIONS SHOULD SEE THE BEST CHANCES THIS
AFTERNOON. HOWEVER...WRF AND HRRR AS WELL AS SOME OTHER SHORT TERM
MODELS POINT TO SECONDARY DEVELOPMENT LATE AS SHORTWAVE ENERGY
DIVES INTO THE NORTHERN SECTIONS. TRIED TO ACCOUNT FOR BOTH
PROJECTIONS WITH HIGHER POPS SOUTH AND NORTH WITH LOWER POPS IN
THE MIDDLE COVERING THE ATLANTA METRO. CAPES GENERALLY AROUND 2000
J/KG TO 3000 J/KG WILL BE POSSIBLE WHICH WILL BE SUFFICIENT TO
FUEL ISOLATED STRONG THUNDERSTORMS. DCAPE LOOKS TO REMAIN BELOW
1000 J/KG BUT ENOUGH PRECIPITATION LOADING WILL BE PRESENT TO
ALLOW FOR MICROBURST POTENTIAL. MORE STORM MOTION TODAY BY A
COUPLE OF KNOTS BUT FEEL BOUNDARY COLLISIONS ALONG WITH LOW FFG
VALUES COULD STILL LEAD TO ISOLATED FLASH FLOODING ACROSS THE AREA.
OHIO VALLEY HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST STATES WITH
RIDGING AND SUBTLE EDGE FEATURE THROUGH THE CAROLINAS AND GEORGIA.
ADDITIONAL DRY AIR SHOULD KEEP FOCUS OF HIGHEST POPS FOR THE
SOUTHERN SECTIONS...EXCEPT NORTHEAST MOUNTAINS WHERE NAMDNG5 SHOWS
ENHANCED DEVELOPMENT DURING THE AFTERNOON.
DEESE
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT IS FORECAST TO MOVE S OF THE AREA SATURDAY EVENING AS
SURFACE HIGH PRESSURE BUILDS ALONG THE EASTERN SEABOARD AND UPPER
LEVEL HIGH PRESSURE BUILDS OVER THE MID U.S. SHOWER AND THUNDERSTORM
CHANCES SHOULD BE HIGHLY DIURNAL SATURDAY NIGHT AND DIMINISH WITH THE
LOSS OF HEATING. SHOWER AND THUNDERSTORM CHANCES LOOK TO BE LIMITED
TO MAINLY CENTRAL GA ON SUNDAY DURING THE AFTERNOON AND EARLY
EVENING HOURS WHERE THE BEST INSTABILITY IS EXPECTED TO BE WITH THE
INFLUENCE OF DRIER AIR AND HIGH PRESSURE HAVING THE MOST AFFECT ON N
GA.
PRECIP CHANCES FOR MONDAY AND TUESDAY LOOK TO BE AS LOW AS WE HAVE
SEEN IN A LONG TIME WITH A GENERALLY DRIER AIRMASS OVER THE AREA AND
THE INFLUENCE OF HIGH PRESSURE. GFS IS MORE AGGRESSIVE WITH PRECIP
AMOUNTS AND CHANCES THAN THE EUROPEAN. WILL NEED TO WATCH THE NE
MOUNTAINS AND FAR S AS AREAS WHERE SMALL CHANCES COULD BE NEEDED.
GFS MORE AGGRESSIVE WITH MOISTURE RETURN ON WEDNESDAY THAN THE
EUROPEAN FROM THE NNW FLOW ALOFT. GUIDANCE FROM HPC FAVORING LOW
POPS FOR N AND PORTIONS OF CENTRAL GA. A SURFACE TROUGH DEVELOPS
ACROSS THE AREA ON THURSDAY AND AGAIN THE GFS IS MORE AGGRESSIVE WITH
THE MOISTURE THAN THE EUROPEAN IN THE NNW FLOW ALOFT. HPC GUIDANCE
FAVORING LOW POPS ACROSS THE ENTIRE AREA DUE TO THE UNCERTAINTY.
BOTH MODELS INDICATING INCREASED MOISTURE OVER THE AREA ON FRIDAY.
TEMPERATURES GENERALLY RUNNING NEAR TO AROUND 6 DEGREES BELOW NORMAL
DURING THIS PERIOD.
BDL
AVIATION...
12Z UPDATE... FOG CONTINUES TO BUILD OVER CENTRAL GEORGIA AS WELL
AS EXTREME NORTH GEORGIA BUT REMAINING OUTSIDE MOST ATL TERMINALS
AT THIS TIME. WILL HOLD FOR NOW WITH VFR CONDITIONS.
OTHERWISE...STILL EXPECTING SHRA AND TSRA DEVELOPMENT THIS
AFTERNOON BUT REDUCED COVERAGE REQUIRING ONLY PROB30 AT THIS
POINT.
//ATL CONFIDENCE...12Z UPDATE... HIGH ON ALL ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 73 84 67 / 40 40 40 20
ATLANTA 89 75 86 70 / 40 40 40 20
BLAIRSVILLE 86 67 81 65 / 50 50 50 20
CARTERSVILLE 90 72 87 69 / 30 30 40 20
COLUMBUS 90 77 88 72 / 50 50 50 20
GAINESVILLE 88 73 83 69 / 40 40 40 20
MACON 91 74 87 71 / 50 50 50 20
ROME 91 72 87 69 / 40 40 40 20
PEACHTREE CITY 88 72 85 69 / 40 40 40 20
VIDALIA 89 75 88 71 / 50 50 50 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
748 AM EDT FRI AUG 23 2013
.PREV DISCUSSION... /ISSUED 348 AM EDT FRI AUG 23 2013/
SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SOUTHEAST SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING
FROM THE EASTERN CAROLINAS THROUGH EXTREME SOUTH GEORGIA WITH WEAK
RIDGING ACROSS THE TENNESSEE VALLEY INTO NORTH GEORGIA. A STRONGER
FRONT IS NOTED TO THE NORTH AS HIGH PRESSURE MOVES INTO THE GREAT
LAKES REGION AND DRIVES FRONT INTO THE OHIO VALLEY AND PORTIONS OF
THE APPALACHIANS. ALTHOUGH NOT COMPLETELY DRY...WATER VAPOR
IMAGERY DOES SHOW SLOT OF DRIER AIR OVER NORTH GEORGIA WHICH ALONG
WITH A LACK OF MID LEVEL FORCING HAS ALLOWED FOR TRANQUIL
OVERNIGHT CONDITIONS. WILL NEED TO WATCH CLOSELY TOWARD DAYBREAK
AS NAM12 CONDENSATION PRESSURE DEFICIT ANALYSIS INDICATES A GOOD
CHANCE OF FOG AND LOW CIGS OVER PORTIONS OF NORTH GEORGIA
INCLUDING THE NORTHERN METRO AND A SEPARATE BATCH COMING UP FROM
THE SOUTH LATE. HAVE ADDED PATCHY FOG TO GRIDS TO COVER FOR NOW
BUT THIS COVERAGE OR INTENSITY MAY NEED TO BE INCREASED.
FOR TODAY...BASED SOLELY ON AVAILABLE MOISTURE AND UTILIZING PWAT
FORECAST...SOUTHERN SECTIONS SHOULD SEE THE BEST CHANCES THIS
AFTERNOON. HOWEVER...WRF AND HRRR AS WELL AS SOME OTHER SHORT TERM
MODELS POINT TO SECONDARY DEVELOPMENT LATE AS SHORTWAVE ENERGY
DIVES INTO THE NORTHERN SECTIONS. TRIED TO ACCOUNT FOR BOTH
PROJECTIONS WITH HIGHER POPS SOUTH AND NORTH WITH LOWER POPS IN
THE MIDDLE COVERING THE ATLANTA METRO. CAPES GENERALLY AROUND 2000
J/KG TO 3000 J/KG WILL BE POSSIBLE WHICH WILL BE SUFFICIENT TO
FUEL ISOLATED STRONG THUNDERSTORMS. DCAPE LOOKS TO REMAIN BELOW
1000 J/KG BUT ENOUGH PRECIPITATION LOADING WILL BE PRESENT TO
ALLOW FOR MICROBURST POTENTIAL. MORE STORM MOTION TODAY BY A
COUPLE OF KNOTS BUT FEEL BOUNDARY COLLISIONS ALONG WITH LOW FFG
VALUES COULD STILL LEAD TO ISOLATED FLASH FLOODING ACROSS THE AREA.
OHIO VALLEY HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST STATES WITH
RIDGING AND SUBTLE EDGE FEATURE THROUGH THE CAROLINAS AND GEORGIA.
ADDITIONAL DRY AIR SHOULD KEEP FOCUS OF HIGHEST POPS FOR THE
SOUTHERN SECTIONS...EXCEPT NORTHEAST MOUNTAINS WHERE NAMDNG5 SHOWS
ENHANCED DEVELOPMENT DURING THE AFTERNOON.
DEESE
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT IS FORECAST TO MOVE S OF THE AREA SATURDAY EVENING AS
SURFACE HIGH PRESSURE BUILDS ALONG THE EASTERN SEABOARD AND UPPER
LEVEL HIGH PRESSURE BUILDS OVER THE MID U.S. SHOWER AND THUNDERSTORM
CHANCES SHOULD BE HIGHLY DIURNAL SATURDAY NIGHT AND DIMINISH WITH THE
LOSS OF HEATING. SHOWER AND THUNDERSTORM CHANCES LOOK TO BE LIMITED
TO MAINLY CENTRAL GA ON SUNDAY DURING THE AFTERNOON AND EARLY
EVENING HOURS WHERE THE BEST INSTABILITY IS EXPECTED TO BE WITH THE
INFLUENCE OF DRIER AIR AND HIGH PRESSURE HAVING THE MOST AFFECT ON N
GA.
PRECIP CHANCES FOR MONDAY AND TUESDAY LOOK TO BE AS LOW AS WE HAVE
SEEN IN A LONG TIME WITH A GENERALLY DRIER AIRMASS OVER THE AREA AND
THE INFLUENCE OF HIGH PRESSURE. GFS IS MORE AGGRESSIVE WITH PRECIP
AMOUNTS AND CHANCES THAN THE EUROPEAN. WILL NEED TO WATCH THE NE
MOUNTAINS AND FAR S AS AREAS WHERE SMALL CHANCES COULD BE NEEDED.
GFS MORE AGGRESSIVE WITH MOISTURE RETURN ON WEDNESDAY THAN THE
EUROPEAN FROM THE NNW FLOW ALOFT. GUIDANCE FROM HPC FAVORING LOW
POPS FOR N AND PORTIONS OF CENTRAL GA. A SURFACE TROUGH DEVELOPS
ACROSS THE AREA ON THURSDAY AND AGAIN THE GFS IS MORE AGGRESSIVE WITH
THE MOISTURE THAN THE EUROPEAN IN THE NNW FLOW ALOFT. HPC GUIDANCE
FAVORING LOW POPS ACROSS THE ENTIRE AREA DUE TO THE UNCERTAINTY.
BOTH MODELS INDICATING INCREASED MOISTURE OVER THE AREA ON FRIDAY.
TEMPERATURES GENERALLY RUNNING NEAR TO AROUND 6 DEGREES BELOW NORMAL
DURING THIS PERIOD.
BDL
.AVIATION...
12Z UPDATE... FOG CONTINUES TO BUILD OVER CENTRAL GEORGIA AS WELL
AS EXTREME NORTH GEORGIA BUT REMAINING OUTSIDE MOST ATL TERMINALS
AT THIS TIME. WILL HOLD FOR NOW WITH VFR CONDITIONS.
OTHERWISE...STILL EXPECTING SHRA AND TSRA DEVELOPMENT THIS
AFTERNOON BUT REDUCED COVERAGE REQUIRING ONLY PROB30 AT THIS
POINT.
//ATL CONFIDENCE...12Z UPDATE... HIGH ON ALL ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 73 84 67 / 40 40 40 20
ATLANTA 89 75 86 70 / 40 40 40 20
BLAIRSVILLE 86 67 81 65 / 50 50 50 20
CARTERSVILLE 90 72 87 69 / 30 30 40 20
COLUMBUS 90 77 88 72 / 50 50 50 20
GAINESVILLE 88 73 83 69 / 40 40 40 20
MACON 91 74 87 71 / 50 50 50 20
ROME 91 72 87 69 / 40 40 40 20
PEACHTREE CITY 88 72 85 69 / 40 40 40 20
VIDALIA 89 75 88 71 / 50 50 50 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
348 AM EDT FRI AUG 23 2013
.SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SOUTHEAST SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING
FROM THE EASTERN CAROLINAS THROUGH EXTREME SOUTH GEORGIA WITH WEAK
RIDGING ACROSS THE TENNESSEE VALLEY INTO NORTH GEORGIA. A STRONGER
FRONT IS NOTED TO THE NORTH AS HIGH PRESSURE MOVES INTO THE GREAT
LAKES REGION AND DRIVES FRONT INTO THE OHIO VALLEY AND PORTIONS OF
THE APPALACHIANS. ALTHOUGH NOT COMPLETELY DRY...WATER VAPOR
IMAGERY DOES SHOW SLOT OF DRIER AIR OVER NORTH GEORGIA WHICH ALONG
WITH A LACK OF MID LEVEL FORCING HAS ALLOWED FOR TRANQUIL
OVERNIGHT CONDITIONS. WILL NEED TO WATCH CLOSELY TOWARD DAYBREAK
AS NAM12 CONDENSATION PRESSURE DEFICIT ANALYSIS INDICATES A GOOD
CHANCE OF FOG AND LOW CIGS OVER PORTIONS OF NORTH GEORGIA
INCLUDING THE NORTHERN METRO AND A SEPARATE BATCH COMING UP FROM
THE SOUTH LATE. HAVE ADDED PATCHY FOG TO GRIDS TO COVER FOR NOW
BUT THIS COVERAGE OR INTENSITY MAY NEED TO BE INCREASED.
FOR TODAY...BASED SOLELY ON AVAILABLE MOISTURE AND UTILIZING PWAT
FORECAST...SOUTHERN SECTIONS SHOULD SEE THE BEST CHANCES THIS
AFTERNOON. HOWEVER...WRF AND HRRR AS WELL AS SOME OTHER SHORT TERM
MODELS POINT TO SECONDARY DEVELOPMENT LATE AS SHORTWAVE ENERGY
DIVES INTO THE NORTHERN SECTIONS. TRIED TO ACCOUNT FOR BOTH
PROJECTIONS WITH HIGHER POPS SOUTH AND NORTH WITH LOWER POPS IN
THE MIDDLE COVERING THE ATLANTA METRO. CAPES GENERALLY AROUND 2000
J/KG TO 3000 J/KG WILL BE POSSIBLE WHICH WILL BE SUFFICIENT TO
FUEL ISOLATED STRONG THUNDERSTORMS. DCAPE LOOKS TO REMAIN BELOW
1000 J/KG BUT ENOUGH PRECIPITATION LOADING WILL BE PRESENT TO
ALLOW FOR MICROBURST POTENTIAL. MORE STORM MOTION TODAY BY A
COUPLE OF KNOTS BUT FEEL BOUNDARY COLLISIONS ALONG WITH LOW FFG
VALUES COULD STILL LEAD TO ISOLATED FLASH FLOODING ACROSS THE AREA.
OHIO VALLEY HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST STATES WITH
RIDGING AND SUBTLE EDGE FEATURE THROUGH THE CAROLINAS AND GEORGIA.
ADDITIONAL DRY AIR SHOULD KEEP FOCUS OF HIGHEST POPS FOR THE
SOUTHERN SECTIONS...EXCEPT NORTHEAST MOUNTAINS WHERE NAMDNG5 SHOWS
ENHANCED DEVELOPMENT DURING THE AFTERNOON.
DEESE
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT IS FORECAST TO MOVE S OF THE AREA SATURDAY EVENING AS
SURFACE HIGH PRESSURE BUILDS ALONG THE EASTERN SEABOARD AND UPPER
LEVEL HIGH PRESSURE BUILDS OVER THE MID U.S. SHOWER AND THUNDERSTORM
CHANCES SHOULD BE HIGHLY DIURNAL SATURDAY NIGHT AND DIMINISH WITH THE
LOSS OF HEATING. SHOWER AND THUNDERSTORM CHANCES LOOK TO BE LIMITED
TO MAINLY CENTRAL GA ON SUNDAY DURING THE AFTERNOON AND EARLY
EVENING HOURS WHERE THE BEST INSTABILITY IS EXPECTED TO BE WITH THE
INFLUENCE OF DRIER AIR AND HIGH PRESSURE HAVING THE MOST AFFECT ON N
GA.
PRECIP CHANCES FOR MONDAY AND TUESDAY LOOK TO BE AS LOW AS WE HAVE
SEEN IN A LONG TIME WITH A GENERALLY DRIER AIRMASS OVER THE AREA AND
THE INFLUENCE OF HIGH PRESSURE. GFS IS MORE AGGRESSIVE WITH PRECIP
AMOUNTS AND CHANCES THAN THE EUROPEAN. WILL NEED TO WATCH THE NE
MOUNTAINS AND FAR S AS AREAS WHERE SMALL CHANCES COULD BE NEEDED.
GFS MORE AGGRESSIVE WITH MOISTURE RETURN ON WEDNESDAY THAN THE
EUROPEAN FROM THE NNW FLOW ALOFT. GUIDANCE FROM HPC FAVORING LOW
POPS FOR N AND PORTIONS OF CENTRAL GA. A SURFACE TROUGH DEVELOPS
ACROSS THE AREA ON THURSDAY AND AGAIN THE GFS IS MORE AGGRESSIVE WITH
THE MOISTURE THAN THE EUROPEAN IN THE NNW FLOW ALOFT. HPC GUIDANCE
FAVORING LOW POPS ACROSS THE ENTIRE AREA DUE TO THE UNCERTAINTY.
BOTH MODELS INDICATING INCREASED MOISTURE OVER THE AREA ON FRIDAY.
TEMPERATURES GENERALLY RUNNING NEAR TO AROUND 6 DEGREES BELOW NORMAL
DURING THIS PERIOD.
BDL
&&
.AVIATION...
06Z UPDATE...
MOISTURE PROFILES FROM VARIOUS MODEL PROJECTIONS SHOW BEST FOG
CHANCES ACROSS EXTREME NORTH GA TO INCLUDE RYY AND PDK BUT
REMAINING JUST OUTSIDE THE REMAINING ATL ARE TAF SITES. WILL BE A
CLOSE CALL BUT WILL KEEP IFR OUT FOR NOW AND MONITOR CLOSELY
THROUGH SUNRISE. ADDITIONAL LOW CLOUDS AND VSBY WILL BE POSSIBLE
OVER THE SOUTHERN SECTIONS AS WELL TO INCLUDE MCN AND CSG.
OTHERWISE...STILL EXPECTING SHRA AND TSRA DEVELOPMENT THIS
AFTERNOON BUT REDUCED COVERAGE REQUIRING ONLY PROB30 AT THIS
POINT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON PRECIP TIMING AND EARLY MORNING VSBYS.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 73 84 67 / 40 40 40 20
ATLANTA 89 75 86 70 / 40 40 40 20
BLAIRSVILLE 86 67 81 65 / 50 50 50 20
CARTERSVILLE 90 72 87 69 / 30 30 40 20
COLUMBUS 90 77 88 72 / 50 50 50 20
GAINESVILLE 88 73 83 69 / 40 40 40 20
MACON 91 74 87 71 / 50 50 50 20
ROME 91 72 87 69 / 40 40 40 20
PEACHTREE CITY 88 72 85 69 / 40 40 40 20
VIDALIA 89 75 88 71 / 50 50 50 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS POCATELLO ID
852 PM MDT SAT AUG 24 2013
.UPDATE...STRONG THUNDERSTORMS FROM THIS AFTERNOON HAVE DECREASED
IN INTENSITY WITH MAINLY ISOLATED CELLS IN EASTERN HIGHLANDS AND
SCATTERED CELLS IN CENTRAL MOUNTAINS. SURFACE FRONTAL BOUNDARY
STRETCHED THROUGH SNAKE PLAIN...WITH WINDS SOMEWHAT ENHANCED THIS
EVENING BY OUTFLOW. SURFACE BOUNDARY SLOWLY PUSHES NORTH THROUGH
REMAINDER OF TONIGHT. NAM CONTINUE TO INDICATE DRYING OVERNIGHT
BUT RECENT HRR MAINTAINS CONVECTION OVER THE CENTRAL MOUNTAINS
PAST MIDNIGHT...STRETCHING AREA OF SHOWERS/THUNDERSTORMS INTO THE
NORTHEAST CORNER OF FORECAST AREA. ADDITIONALLY...WEAK SHOWERS
PAINTED BY HRRR ALONG SOUTHERN EDGE OF FORECAST AREA AFTER
MIDNIGHT AS WELL. WV IMAGERY SHOWS SURGE OF MOISTURE ASSOCIATED
WITH SHORTWAVE MOVING QUICKLY NORTH THROUGH CENTRAL NEVADA THIS
EVENING WHICH LENDS CREDENCE TO THESE IDEAS. THEREFORE LEFT WEAK
POPS HIGHER ELEVATIONS MOST AREAS REMAINDER OF TONIGHT. HAVE MADE
SOME MINOR ADJUSTMENTS FOR SAT/RADAR TRENDS WITH NO FURTHER
UPDATES ANTICIPATED THIS EVENING. DMH
&&
.PREV DISCUSSION... /ISSUED 207 PM MDT SAT AUG 24 2013/
SHORT TERM...FOR THIS AFTERNOON AND EVENING WATCHING THE
DISTURBANCE IN SOUTHWEST FLOW CROSSING FROM CALIFORNIA INTO
NEVADA. THERE IS ALSO A DISTURBANCE IN SOUTH CENTRAL AND EASTERN
NEVADA MOVING NORTH WHERE LIGHTNING ACTIVITY HAS ALREADY BEGUN.
CONVECTION SHOULD BEGIN EARLY THIS AFTERNOON BETWEEN OAKLEY AND
SUN VALLEY. MODEL SOUNDINGS IN THAT AREA SHOWING HIGHER CAPE
1200-1300 J/KG THAN YESTERDAY WITH MODEST VERTICAL SHEAR THIS
AFTERNOON TO SUPPORT STRONG CONVECTION. GOES SOUNDER INFORMATION
HAS BEEN SHOWING UNSTABLE ENVIRONMENT PAST FEW HOURS. CONVECTION
IN THE CARIBOU HIGHLANDS AREA COULD BE HELD BACK SOME AS THE UPPER
LEVEL WINDS LEAVE THAT AREA IN CONVERGENCE ALOFT AND LESS SUPPORT
FOR THUNDERSTORMS. SOUTHERLY BOUNDARY LAYER WINDS HAVE BEEN
INCREASING FROM AROUND WENDOVER INTO THE BURLEY AREA THE NAM12
CONTINUES THIS TREND THROUGH WELL PAST MIDNIGHT. THEREFORE
INCREASED MORNING LOW TEMPERATURES ALONG THE FOOT HILLS FROM
BURLEY TO POCATELLO. THE INCREASED SOUTHERLY FLOW SHOULD ALSO ADD
UPSLOPE FLOW TO SUPPORT SHOWERS IN THE UPPER SNAKE HIGHLANDS
TONIGHT THAT MAY LAST PAST MIDNIGHT.
SUNDAY...WATCHING TROPICAL STORM IVO OFF BAJA...MODELS BRING SOME
OF THIS MOISTURE TOWARDS EVANSTON WYOMING BY SUNDAY AFTERNOON.
WHILE SOME OF THIS MOISTURE WILL MISS THIS AREA...THE NAM12
SUGGEST A SPOKE OF ENERGY OFF THE CALIFORNIA COAST TROUGH WILL ACT
TO PULL SOME OF THAT MOISTURE NORTH TOWARDS SUN VALLEY AREA SUNDAY
AFTERNOON AND EVENING. INCREASED SHOWERS AND THUNDERSTORMS TO
SCATTERED TOWARDS THAT AREA AND WE COULD SEE SOME .1 TO .2 INCH
RAIN AMOUNTS FROM THUNDERSTORMS.
LONG TERM...SOUTHEAST IDAHO REMAINS SQUEEZED IN THE FLOW BETWEEN
THE HIGH CENTERED OVER KANSAS AND THE LOW OFF SHORE WITH MONSOON
MOISTURE PROVIDING AN UNSTABLE AIR MASS THE NEXT FEW DAYS. THERE IS
STILL A HINT OF ANOTHER TROPICAL WAVE CROSSING CENTRAL AMERICA BY
FRIDAY. HOWEVER THE NORTHWARD SURGE OF MOISTURE INTO THE GREAT
BASIN APPEARS MORE FRAGMENTED THAN SHOWN BY MODELS YESTERDAY. RS
AVIATION...HAVE VICINITY THUNDERSTORMS ALL TAF SITES AGAIN THIS
AFTERNOON THROUGH 04Z. THINK SUN MOST LIKELY SITE TO HAVE ON
STATION TODAY. VFR CONDITIONS OUTSIDE THUNDERSTORMS. EXPECT
SIMILAR CONDITIONS SUNDAY WITH ISOLATED TO SCATTERED STORMS ONCE
AGAIN.
GK
FIRE WEATHER...SOUTHERLY FLOW ALOFT CONTINUES TO PUSH MOISTURE INTO
SOUTHEAST IDAHO. RED FLAG WARNINGS REMAIN IN EFFECT UNTIL 10 PM
THIS EVENING FOR SCATTERED THUNDERSTORMS. SOUTHERLY FLOW CONTINUES
THROUGH MOST OF NEXT WEEK WITH ISOLATED TO SCATTERED THUNDERSTORMS
EXPECTED DAILY THROUGH WEDNESDAY. MAY SEE LESS COVERAGE ON MONDAY
WITH SOME DRIER AIR TEMPORARILY MOVING INTO THE REGION.
GK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING
IDZ410-413-422-425-427-475-476.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1256 PM CDT FRI AUG 23 2013
.DISCUSSION...
352 AM CDT
SYNOPSIS...A LARGE RIDGE OVER THE CENTRAL US SPREADS EAST OVER THE
GREAT LAKES. A WARMING TREND IS IN STORE THROUGH MID NEXT WEEK WITH
HIGHS IN THE 90S AND HEAT INDICES IN THE 100S POSSIBLE.
TODAY...
HIGH PRESSURE IS OVER THE GREAT LAKES WITH A LARGE RIDGE ALOFT
CENTERED OVER THE SOUTH CENTRAL GREAT PLAINS. PRIMARILY CLEAR SKIES
OVERNIGHT COMBINED WITH WEAK TO CALM WINDS AND WET GROUND RESULTED
IN AREAS TO WIDESPREAD DENSE FOG. HIGH LEVEL CIRRUS OVER THE
EASTERN AND SOUTHERN PORTIONS OF THE CWA HAVE LIMITED FOG
DEVELOPMENT A BIT AND RADIATIONAL COOLING. HOWEVER EXPECTING FOG TO
BURN OFF QUICKLY THIS MORNING LEADING TO A DRY AND PLEASANT DAY WITH
HIGHS IN THE LOW 80S. WINDS WILL BE OFF OF THE LAKE THEREFORE TEMPS
WILL BE A FEW DEGREES COOLER ALONG THE LAKE FRONT BUT STILL BE IN
THE UPPER 70S TO AROUND 80.
REGARDING THE BEACH HAZARDS STATEMENT...THE NORTHEAST WINDS HAVE
BEEN SLOW TO INCREASE BUT WILL THIS MORNING TO 10 TO 15 MPH ALONG
THE LAKE SHORE AS THE SURFACE HIGH BUILDS SOUTHWARD. THE WAVE
MAXIMUM AS DEPICTED BY OUR WAVE MODEL MOVES INTO THE COOK AND LAKE
COUNTY INDIANA SHORELINE. WAVE HEIGHTS WILL BE A BIT MORE MARGINAL
THAN ORIGINALLY THOUGHT...MAINLY 3 TO 4 FT BUT WAVE OCCASIONALLY
TOPPING THAT ARE STILL EXPECTED. HAVE CANCELLED PORTER COUNTY FROM
THE HEADLINE THOUGH GIVEN THE TRAJECTORY OF THE WAVE MAXIMUM.
SATURDAY THROUGH MONDAY...
THE UPPER LEVEL RIDGE EXPANDS OVER THE LOT CWA LATE TONIGHT INTO
SATURDAY MORNING BUT REMAINS CENTERED OVER THE OZARKS/SOUTH CENTRAL
PLAINS THROUGH THE REST OF THE FORECAST PERIOD. THE SURFACE HIGH
PRESSURE CURRENTLY OVER THE GREAT LAKES SHIFTS EAST FRIDAY NIGHT
INTO SUNDAY AND THEN SLIDES SOUTH BECOMING CENTERED OVER THE
SOUTHEAST ATLANTIC COAST MONDAY NIGHT.
MULTIPLE SHORTWAVES WILL ROTATE AROUND THE NORTHERN PORTION OF THE
RIDGE WITH THE FIRST ONE SCOOTING NORTH OF THE CWA SATURDAY NIGHT.
ADDITIONAL CONVECTION IS EXPECTED ACROSS NORTHERN WI...MI...AND THE
NORTHERN HALF OF THE LAKE THROUGH SUNDAY NIGHT. CONVECTION SPREADS
DOWN THE LENGTH OF THE LAKE MONDAY AS THE SURFACE HIGH SHIFTS SOUTH
AND A BROAD SURFACE LOW OVER THE DAKOTAS SLOWLY SPREADS EAST.
HOWEVER NOT ANTICIPATING ANY PRECIP OVER THE LAND PORTION OF THE LOT
CWA.
UPPER LEVEL TEMPS SLOWLY BUILD WITH 925MB TEMPS REACHING 24-28C ON
MONDAY. LOCAL CLIMATOLOGY GUIDANCE SUGGESTS TEMPS SHOULD EASILY
REACH THE LOW 90S ON MONDAY. FORECAST SOUNDINGS ALSO INDICATE
DEWPOINTS MAY BE A BIT LOWER THAN CURRENTLY FORECAST DUE TO MIXING.
THEREFORE KEPT DEWPOINTS A BIT LOWER THAN GUIDANCE WITH MAX HEAT
INDICES IN THE UPPER 90S TO AROUND 100.
LONG TERM...TUESDAY THROUGH THURSDAY...
THE UPPER LEVEL RIDGE REMAINS IN PLACE THROUGH THE EXTENDED BUT A
BROAD AREA OF LOW PRESSURE WEAKENS AS IT APPROACHES THE REGION.
GUIDANCE IS STILL VERY FUZZY ON WHERE EXACTLY THIS LOW WILL TRACK
AND HOW IT WILL IMPACT HIGH TEMPS THROUGH MID WEEK. FOR NOW STILL
EXPECTING TEMPS TO CLIMB. 925MB TEMPS REACH 26-30C ALOFT AND
EXPECTING THE PEAK OF THE HEAT TO BE TUESDAY AND WEDNESDAY WITH HIGH
TEMPS IN THE LOW TO MID 90S. DEWPOINTS WILL BE AROUND 70 RESULTING
IN HEAT INDICES AROUND 100-105F. WILL CONTINUE TO MONITOR MODEL
TRENDS AS CLOUD COVER AND/OR THE WEAK LOW COULD LIMIT WARMING ON
WEDNESDAY...BUT TUESDAY CERTAINLY LOOKS HOT.
A WEAK BACKDOOR COLD FRONT MAY MOVE THROUGH THE REGION WEDNESDAY
INTO THURSDAY WITH DRIER AND SLIGHTLY COOLER CONDITIONS EXPECTED.
TEMPS LOOK LIKE THEY WILL BE IN THE LOW 90S BUT WITH DRIER
CONDITIONS...HEAT INDICES IN THE MID TO UPPER 90S ARE EXPECTED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* EAST TO NORTHEAST WINDS ARND 10-14KT THIS AFTERNOON DIMINISH
ARND SUNSET TO 3-5KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE OVERHEAD WILL CONTINUE TO PROVIDE OPTIMAL FLYING
CONDITIONS TO NORTHERN IL/NORTHWEST IN AIRFIELDS. VISIBLE IMAGERY
CONTINUES TO INDICATE NEAR CLOUDLESS SKIES FOR THE AREA
AIRFIELDS...AND IS EXPECTED TO PERSIST OVERNIGHT INTO SATURDAY.
EAST WINDS WITH SPEEDS GENERALLY AROUND 10-14KT WILL QUICKLY
DIMINISH TO ARND 3-5KT OVERNIGHT...THEN BEGIN TO TURN SLIGHTLY TO
THE SOUTHEAST. A FEW LOCATIONS COULD SEE SOME PATCHY GROUND FOG
DEVELOP AGAIN OVERNIGHT...HOWEVER THIS SHOULD BE LIMITED AND NOT
IMPACT THE TAF SITES. THEN AFTER DAYBREAK SATURDAY WINDS WILL
SLOWLY INCREASE FROM THE SOUTHEAST/EAST TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-MONDAY...VFR.
TUESDAY-WEDNESDAY...VFR AND HOT DURING THE DAYS. SLIGHT CHC OF
STORMS WED NIGHT.
THURSDAY...VFR.
MTF
&&
.MARINE...
306 AM CDT
HIGH PRESSURE WILL EXPAND ITS WAY DOWN THE LAKE TODAY LEADING TO
NORTHEAST WINDS ACROSS NEARSHORE AREAS WHILE DIMINISHING WINDS
OVER THE OPEN WATER. AS THE HIGH DEPARTS OFF TO THE EAST IT WILL
STALL WITH BROAD LOW PRESSURE DEVELOPING OVER THE NORTHERN PLAINS.
THIS PATTERN WILL PERSIST INTO NEXT WEEK MEANING PROLONGED
SOUTHERLY FLOW OVER THE LAKE. SOME 30 KT GUSTS IN THE NORTH ON
SUNDAY COULD BE SEEN. THIS OVERALL WEATHER PATTERN CAN AT TIMES
LEAD TO A STRONG COMPLEX OR TWO OF STORMS FOR THE NORTHERN PART OF
THE LAKE...AND THAT WOULD SEEM MOST FAVORED SOMETIME IN THE MON
NIGHT-WED NIGHT TIME FRAME...THOUGH CONFIDENCE ON THIS REMAINS
LOW. EVENTUALLY THE BROAD LOW WILL SHIFT OVER THE LAKE DURING THE
MIDWEEK PERIOD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1216 PM CDT Fri Aug 23 2013
.DISCUSSION...
ISSUED 949 AM CDT Fri Aug 23 2013
Areas of dense fog north of I-74 has been lifting into a stratus
deck this morning, and should continue to thin from the edges over
the next couple hours as diurnal mixing increases. Otherwise, high
pressure north of Lake Superior will bring a 5-10 mph northeast
wind flow to the region causing dewpoints will gradually fall into
the low/mid 60s from north to south by late afternoon. Subsidence
on the south side of the ridge should provide mostly sunny skies
and seasonable highs in the mid 80s.
&&
.AVIATION...
ISSUED 1216 PM CDT Fri Aug 23 2013
High pressure over the northern Great Lakes will bring mostly
clear skies and east winds under 10 kts to the terminals through
18z/Sat. MVFR fog will be possible within a few hours of sunrise.
25
&&
.PREV DISCUSSION...
ISSUED 240 AM CDT Fri Aug 23 2013
SHORT TERM...Today through Saturday...
Initial frontal passage has taken place over all of central and
southeast Illinois early this morning, but drier air lingers a bit
further back as lower 60s dew points now starting to enter the far
northern CWA. A cluster of thunderstorms developed from
Springfield to Decatur along the remnants of an old boundary from
earlier, in an area with MUCAPE`s of around 1000 J/kg, and the
cluster has been increasing a bit over the last hour or so as it
moves south-southeast. Latest model guidance suggesting scattered
showers/storms through about mid morning over about the southeast
third of the forecast area.
Further north, fog has been thickening and increasing over the
northeast third of the state, where skies have cleared and the
drier air has arrived. So far visibilities in our area have been
staying up as a band of altocumulus has persisted, but clearing
has been taking place from Galesburg to Lacon. However, the lower
visibilities have been in areas that had quite a bit of rain on
Thursday, and much of our forecast area had a quarter inch or less
except in isolated spots. So, the question is how much of the
forecast area, if any, will see dense fog this morning. HRRR
guidance is the most pessimistic with it fairly widespread along
and north of I-74, while the most recent RAP has scaled back and
went mainly patchy dense fog in the same area. Currently have
mention of 1/2 mile visibility in fog in this area through about 9
am, but will have to monitor for any significant advection from
the northeast.
Once the fog and rain moves out, quiet weather expected through
the first part of the weekend. High pressure drifting through the
Great Lakes will advect some drier air in from the east, but
should still see highs in the mid-upper 80s.
LONG TERM...Sunday through Thursday...
Main weather story over the coming week continues to be with the
expanding heat over the center of the nation, as a large dome of
high pressure aloft drifts eastward. Any MCS ridge riders will be
well to our north, and will continue the dry forecast for next
week. Highs to rise through the 90s much of the week as thermal
ridge builds eastward. Core of this ridge will be in the area on
Wednesday. Latest ECMWF showing upper 90s over most of the
forecast area that day. Have continued to trend temperatures up a
degree or two from blended guidance with mid 90s widespread on
Wednesday. Heat index values of just over 100 likely across the
western CWA Monday-Tuesday and everywhere Wednesday. On Thursday,
the thermal ridge starts shifting westward again, but should still
see highs in the 93-95 range.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1114 AM CDT FRI AUG 23 2013
.DISCUSSION...
352 AM CDT
SYNOPSIS...A LARGE RIDGE OVER THE CENTRAL US SPREADS EAST OVER THE
GREAT LAKES. A WARMING TREND IS IN STORE THROUGH MID NEXT WEEK WITH
HIGHS IN THE 90S AND HEAT INDICES IN THE 100S POSSIBLE.
TODAY...
HIGH PRESSURE IS OVER THE GREAT LAKES WITH A LARGE RIDGE ALOFT
CENTERED OVER THE SOUTH CENTRAL GREAT PLAINS. PRIMARILY CLEAR SKIES
OVERNIGHT COMBINED WITH WEAK TO CALM WINDS AND WET GROUND RESULTED
IN AREAS TO WIDESPREAD DENSE FOG. HIGH LEVEL CIRRUS OVER THE
EASTERN AND SOUTHERN PORTIONS OF THE CWA HAVE LIMITED FOG
DEVELOPMENT A BIT AND RADIATIONAL COOLING. HOWEVER EXPECTING FOG TO
BURN OFF QUICKLY THIS MORNING LEADING TO A DRY AND PLEASANT DAY WITH
HIGHS IN THE LOW 80S. WINDS WILL BE OFF OF THE LAKE THEREFORE TEMPS
WILL BE A FEW DEGREES COOLER ALONG THE LAKE FRONT BUT STILL BE IN
THE UPPER 70S TO AROUND 80.
REGARDING THE BEACH HAZARDS STATEMENT...THE NORTHEAST WINDS HAVE
BEEN SLOW TO INCREASE BUT WILL THIS MORNING TO 10 TO 15 MPH ALONG
THE LAKE SHORE AS THE SURFACE HIGH BUILDS SOUTHWARD. THE WAVE
MAXIMUM AS DEPICTED BY OUR WAVE MODEL MOVES INTO THE COOK AND LAKE
COUNTY INDIANA SHORELINE. WAVE HEIGHTS WILL BE A BIT MORE MARGINAL
THAN ORIGINALLY THOUGHT...MAINLY 3 TO 4 FT BUT WAVE OCCASIONALLY
TOPPING THAT ARE STILL EXPECTED. HAVE CANCELLED PORTER COUNTY FROM
THE HEADLINE THOUGH GIVEN THE TRAJECTORY OF THE WAVE MAXIMUM.
SATURDAY THROUGH MONDAY...
THE UPPER LEVEL RIDGE EXPANDS OVER THE LOT CWA LATE TONIGHT INTO
SATURDAY MORNING BUT REMAINS CENTERED OVER THE OZARKS/SOUTH CENTRAL
PLAINS THROUGH THE REST OF THE FORECAST PERIOD. THE SURFACE HIGH
PRESSURE CURRENTLY OVER THE GREAT LAKES SHIFTS EAST FRIDAY NIGHT
INTO SUNDAY AND THEN SLIDES SOUTH BECOMING CENTERED OVER THE
SOUTHEAST ATLANTIC COAST MONDAY NIGHT.
MULTIPLE SHORTWAVES WILL ROTATE AROUND THE NORTHERN PORTION OF THE
RIDGE WITH THE FIRST ONE SCOOTING NORTH OF THE CWA SATURDAY NIGHT.
ADDITIONAL CONVECTION IS EXPECTED ACROSS NORTHERN WI...MI...AND THE
NORTHERN HALF OF THE LAKE THROUGH SUNDAY NIGHT. CONVECTION SPREADS
DOWN THE LENGTH OF THE LAKE MONDAY AS THE SURFACE HIGH SHIFTS SOUTH
AND A BROAD SURFACE LOW OVER THE DAKOTAS SLOWLY SPREADS EAST.
HOWEVER NOT ANTICIPATING ANY PRECIP OVER THE LAND PORTION OF THE LOT
CWA.
UPPER LEVEL TEMPS SLOWLY BUILD WITH 925MB TEMPS REACHING 24-28C ON
MONDAY. LOCAL CLIMATOLOGY GUIDANCE SUGGESTS TEMPS SHOULD EASILY
REACH THE LOW 90S ON MONDAY. FORECAST SOUNDINGS ALSO INDICATE
DEWPOINTS MAY BE A BIT LOWER THAN CURRENTLY FORECAST DUE TO MIXING.
THEREFORE KEPT DEWPOINTS A BIT LOWER THAN GUIDANCE WITH MAX HEAT
INDICES IN THE UPPER 90S TO AROUND 100.
LONG TERM...TUESDAY THROUGH THURSDAY...
THE UPPER LEVEL RIDGE REMAINS IN PLACE THROUGH THE EXTENDED BUT A
BROAD AREA OF LOW PRESSURE WEAKENS AS IT APPROACHES THE REGION.
GUIDANCE IS STILL VERY FUZZY ON WHERE EXACTLY THIS LOW WILL TRACK
AND HOW IT WILL IMPACT HIGH TEMPS THROUGH MID WEEK. FOR NOW STILL
EXPECTING TEMPS TO CLIMB. 925MB TEMPS REACH 26-30C ALOFT AND
EXPECTING THE PEAK OF THE HEAT TO BE TUESDAY AND WEDNESDAY WITH HIGH
TEMPS IN THE LOW TO MID 90S. DEWPOINTS WILL BE AROUND 70 RESULTING
IN HEAT INDICES AROUND 100-105F. WILL CONTINUE TO MONITOR MODEL
TRENDS AS CLOUD COVER AND/OR THE WEAK LOW COULD LIMIT WARMING ON
WEDNESDAY...BUT TUESDAY CERTAINLY LOOKS HOT.
A WEAK BACKDOOR COLD FRONT MAY MOVE THROUGH THE REGION WEDNESDAY
INTO THURSDAY WITH DRIER AND SLIGHTLY COOLER CONDITIONS EXPECTED.
TEMPS LOOK LIKE THEY WILL BE IN THE LOW 90S BUT WITH DRIER
CONDITIONS...HEAT INDICES IN THE MID TO UPPER 90S ARE EXPECTED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NE/ENE WINDS AROUND 10 KT MAY INCREASE TO 12-14KT BY EARLY THIS
AFTERNOON.
BEACHLER
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE CONTINUES TO BUILD SOUTHEAST FROM THE UPPER
MISSISSIPPI VALLEY. DRIER AIR OOZING IN FROM THIS HAS HELPED TO
ABATE THE FOG ACROSS MOST OF THE TAF SITES EARLY THIS MORNING.
SOME STRATUS ACROSS GYY AND JUST SOUTH OF MDW SHOULD QUICKLY TURN
INTO A CU FIELD THIS MORNING. THE HIGH WILL TRANSLATE SLOWLY EAST
THROUGH THE TAF PERIOD. WINDS WILL PICK UP DURING THE MID TO LATE
MORNING WITH THE VAD WIND PROFILE INDICATING 10-15KT WITHIN 2000
FT OF THE SURFACE. THE WINDS WILL BE OFF THE LAKE AS WELL...AND
CLIMATOLOGY POINTS TO THE DIRECTION BEING CLOSER TO ENE OR EVEN E
BY AFTERNOON. SPEEDS SHOULD DIMINISH QUICKLY COME THIS EVE. FOG
WILL BE LESS OF A THREAT TONIGHT DUE TO DRYING IN THE LOW-
LEVELS...BUT STILL SOME PATCHY FOG MAY BE SEEN ESPECIALLY IN THOSE
AREAS THAT SAW MORE OF AN APPRECIABLE RAIN DURING THURSDAY /LIKE
RFD/.
MTF
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE THAT BROKEN STRATUS WILL STAY JUST SOUTH OF
MDW.
* MEDIUM CONFIDENCE IN WIND SPEEDS STAY AOB 10KT TODAY.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-MONDAY...VFR.
TUESDAY-WEDNESDAY...VFR AND HOT DURING THE DAYS. SLIGHT CHC OF
STORMS WED NIGHT.
THURSDAY...VFR.
MTF
&&
.MARINE...
306 AM CDT
HIGH PRESSURE WILL EXPAND ITS WAY DOWN THE LAKE TODAY LEADING TO
NORTHEAST WINDS ACROSS NEARSHORE AREAS WHILE DIMINISHING WINDS
OVER THE OPEN WATER. AS THE HIGH DEPARTS OFF TO THE EAST IT WILL
STALL WITH BROAD LOW PRESSURE DEVELOPING OVER THE NORTHERN PLAINS.
THIS PATTERN WILL PERSIST INTO NEXT WEEK MEANING PROLONGED
SOUTHERLY FLOW OVER THE LAKE. SOME 30 KT GUSTS IN THE NORTH ON
SUNDAY COULD BE SEEN. THIS OVERALL WEATHER PATTERN CAN AT TIMES
LEAD TO A STRONG COMPLEX OR TWO OF STORMS FOR THE NORTHERN PART OF
THE LAKE...AND THAT WOULD SEEM MOST FAVORED SOMETIME IN THE MON
NIGHT-WED NIGHT TIME FRAME...THOUGH CONFIDENCE ON THIS REMAINS
LOW. EVENTUALLY THE BROAD LOW WILL SHIFT OVER THE LAKE DURING THE
MIDWEEK PERIOD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
950 AM CDT Fri Aug 23 2013
.DISCUSSION...
ISSUED 949 AM CDT Fri Aug 23 2013
Areas of dense fog north of I-74 has been lifting into a stratus
deck this morning, and should continue to thin from the edges over
the next couple hours as diurnal mixing increases. Otherwise, high
pressure north of Lake Superior will bring a 5-10 mph northeast
wind flow to the region causing dewpoints will gradually fall into
the low/mid 60s from north to south by late afternoon. Subsidence
on the south side of the ridge should provide mostly sunny skies
and seasonable highs in the mid 80s.
25
&&
.AVIATION...
ISSUED 657 AM CDT Fri Aug 23 2013
Generally quiet/VFR aviation weather conditions expected across
the central Illinois terminals through the 12Z TAF valid time.
Patchy fog/stratus may briefly cause MVFR/IFR conditions for a
couple hours this morning, but otherwise cloud cover should be
minimal. While light fog can not be ruled out overnight tonight,
the drier air filtering into the area around the south side of a
an area high pressure should keep the risk to a minimum.
Bak
&&
.PREV DISCUSSION...
ISSUED 240 AM CDT Fri Aug 23 2013
SHORT TERM...Today through Saturday...
Initial frontal passage has taken place over all of central and
southeast Illinois early this morning, but drier air lingers a bit
further back as lower 60s dew points now starting to enter the far
northern CWA. A cluster of thunderstorms developed from
Springfield to Decatur along the remnants of an old boundary from
earlier, in an area with MUCAPE`s of around 1000 J/kg, and the
cluster has been increasing a bit over the last hour or so as it
moves south-southeast. Latest model guidance suggesting scattered
showers/storms through about mid morning over about the southeast
third of the forecast area.
Further north, fog has been thickening and increasing over the
northeast third of the state, where skies have cleared and the
drier air has arrived. So far visibilities in our area have been
staying up as a band of altocumulus has persisted, but clearing
has been taking place from Galesburg to Lacon. However, the lower
visibilities have been in areas that had quite a bit of rain on
Thursday, and much of our forecast area had a quarter inch or less
except in isolated spots. So, the question is how much of the
forecast area, if any, will see dense fog this morning. HRRR
guidance is the most pessimistic with it fairly widespread along
and north of I-74, while the most recent RAP has scaled back and
went mainly patchy dense fog in the same area. Currently have
mention of 1/2 mile visibility in fog in this area through about 9
am, but will have to monitor for any significant advection from
the northeast.
Once the fog and rain moves out, quiet weather expected through
the first part of the weekend. High pressure drifting through the
Great Lakes will advect some drier air in from the east, but
should still see highs in the mid-upper 80s.
LONG TERM...Sunday through Thursday...
Main weather story over the coming week continues to be with the
expanding heat over the center of the nation, as a large dome of
high pressure aloft drifts eastward. Any MCS ridge riders will be
well to our north, and will continue the dry forecast for next
week. Highs to rise through the 90s much of the week as thermal
ridge builds eastward. Core of this ridge will be in the area on
Wednesday. Latest ECMWF showing upper 90s over most of the
forecast area that day. Have continued to trend temperatures up a
degree or two from blended guidance with mid 90s widespread on
Wednesday. Heat index values of just over 100 likely across the
western CWA Monday-Tuesday and everywhere Wednesday. On Thursday,
the thermal ridge starts shifting westward again, but should still
see highs in the 93-95 range.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 AM CDT FRI AUG 23 2013
.DISCUSSION...
352 AM CDT
SYNOPSIS...A LARGE RIDGE OVER THE CENTRAL US SPREADS EAST OVER THE
GREAT LAKES. A WARMING TREND IS IN STORE THROUGH MID NEXT WEEK WITH
HIGHS IN THE 90S AND HEAT INDICES IN THE 100S POSSIBLE.
TODAY...
HIGH PRESSURE IS OVER THE GREAT LAKES WITH A LARGE RIDGE ALOFT
CENTERED OVER THE SOUTH CENTRAL GREAT PLAINS. PRIMARILY CLEAR SKIES
OVERNIGHT COMBINED WITH WEAK TO CALM WINDS AND WET GROUND RESULTED
IN AREAS TO WIDESPREAD DENSE FOG. HIGH LEVEL CIRRUS OVER THE
EASTERN AND SOUTHERN PORTIONS OF THE CWA HAVE LIMITED FOG
DEVELOPMENT A BIT AND RADIATIONAL COOLING. HOWEVER EXPECTING FOG TO
BURN OFF QUICKLY THIS MORNING LEADING TO A DRY AND PLEASANT DAY WITH
HIGHS IN THE LOW 80S. WINDS WILL BE OFF OF THE LAKE THEREFORE TEMPS
WILL BE A FEW DEGREES COOLER ALONG THE LAKE FRONT BUT STILL BE IN
THE UPPER 70S TO AROUND 80.
REGARDING THE BEACH HAZARDS STATEMENT...THE NORTHEAST WINDS HAVE
BEEN SLOW TO INCREASE BUT WILL THIS MORNING TO 10 TO 15 MPH ALONG
THE LAKE SHORE AS THE SURFACE HIGH BUILDS SOUTHWARD. THE WAVE
MAXIMUM AS DEPICTED BY OUR WAVE MODEL MOVES INTO THE COOK AND LAKE
COUNTY INDIANA SHORELINE. WAVE HEIGHTS WILL BE A BIT MORE MARGINAL
THAN ORIGINALLY THOUGHT...MAINLY 3 TO 4 FT BUT WAVE OCCASIONALLY
TOPPING THAT ARE STILL EXPECTED. HAVE CANCELLED PORTER COUNTY FROM
THE HEADLINE THOUGH GIVEN THE TRAJECTORY OF THE WAVE MAXIMUM.
SATURDAY THROUGH MONDAY...
THE UPPER LEVEL RIDGE EXPANDS OVER THE LOT CWA LATE TONIGHT INTO
SATURDAY MORNING BUT REMAINS CENTERED OVER THE OZARKS/SOUTH CENTRAL
PLAINS THROUGH THE REST OF THE FORECAST PERIOD. THE SURFACE HIGH
PRESSURE CURRENTLY OVER THE GREAT LAKES SHIFTS EAST FRIDAY NIGHT
INTO SUNDAY AND THEN SLIDES SOUTH BECOMING CENTERED OVER THE
SOUTHEAST ATLANTIC COAST MONDAY NIGHT.
MULTIPLE SHORTWAVES WILL ROTATE AROUND THE NORTHERN PORTION OF THE
RIDGE WITH THE FIRST ONE SCOOTING NORTH OF THE CWA SATURDAY NIGHT.
ADDITIONAL CONVECTION IS EXPECTED ACROSS NORTHERN WI...MI...AND THE
NORTHERN HALF OF THE LAKE THROUGH SUNDAY NIGHT. CONVECTION SPREADS
DOWN THE LENGTH OF THE LAKE MONDAY AS THE SURFACE HIGH SHIFTS SOUTH
AND A BROAD SURFACE LOW OVER THE DAKOTAS SLOWLY SPREADS EAST.
HOWEVER NOT ANTICIPATING ANY PRECIP OVER THE LAND PORTION OF THE LOT
CWA.
UPPER LEVEL TEMPS SLOWLY BUILD WITH 925MB TEMPS REACHING 24-28C ON
MONDAY. LOCAL CLIMATOLOGY GUIDANCE SUGGESTS TEMPS SHOULD EASILY
REACH THE LOW 90S ON MONDAY. FORECAST SOUNDINGS ALSO INDICATE
DEWPOINTS MAY BE A BIT LOWER THAN CURRENTLY FORECAST DUE TO MIXING.
THEREFORE KEPT DEWPOINTS A BIT LOWER THAN GUIDANCE WITH MAX HEAT
INDICES IN THE UPPER 90S TO AROUND 100.
LONG TERM...TUESDAY THROUGH THURSDAY...
THE UPPER LEVEL RIDGE REMAINS IN PLACE THROUGH THE EXTENDED BUT A
BROAD AREA OF LOW PRESSURE WEAKENS AS IT APPROACHES THE REGION.
GUIDANCE IS STILL VERY FUZZY ON WHERE EXACTLY THIS LOW WILL TRACK
AND HOW IT WILL IMPACT HIGH TEMPS THROUGH MID WEEK. FOR NOW STILL
EXPECTING TEMPS TO CLIMB. 925MB TEMPS REACH 26-30C ALOFT AND
EXPECTING THE PEAK OF THE HEAT TO BE TUESDAY AND WEDNESDAY WITH HIGH
TEMPS IN THE LOW TO MID 90S. DEWPOINTS WILL BE AROUND 70 RESULTING
IN HEAT INDICES AROUND 100-105F. WILL CONTINUE TO MONITOR MODEL
TRENDS AS CLOUD COVER AND/OR THE WEAK LOW COULD LIMIT WARMING ON
WEDNESDAY...BUT TUESDAY CERTAINLY LOOKS HOT.
A WEAK BACKDOOR COLD FRONT MAY MOVE THROUGH THE REGION WEDNESDAY
INTO THURSDAY WITH DRIER AND SLIGHTLY COOLER CONDITIONS EXPECTED.
TEMPS LOOK LIKE THEY WILL BE IN THE LOW 90S BUT WITH DRIER
CONDITIONS...HEAT INDICES IN THE MID TO UPPER 90S ARE EXPECTED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NE/ENE WINDS AROUND 10 KT LATE THIS MORNING THEN SPEEDS MAY
INCREASE TO 12-14KT BY EARLY THIS AFTERNOON.
BEACHLER
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE CONTINUES TO BUILD SOUTHEAST FROM THE UPPER
MISSISSIPPI VALLEY. DRIER AIR OOZING IN FROM THIS HAS HELPED TO
ABATE THE FOG ACROSS MOST OF THE TAF SITES EARLY THIS MORNING.
SOME STRATUS ACROSS GYY AND JUST SOUTH OF MDW SHOULD QUICKLY TURN
INTO A CU FIELD THIS MORNING. THE HIGH WILL TRANSLATE SLOWLY EAST
THROUGH THE TAF PERIOD. WINDS WILL PICK UP DURING THE MID TO LATE
MORNING WITH THE VAD WIND PROFILE INDICATING 10-15KT WITHIN 2000
FT OF THE SURFACE. THE WINDS WILL BE OFF THE LAKE AS WELL...AND
CLIMATOLOGY POINTS TO THE DIRECTION BEING CLOSER TO ENE OR EVEN E
BY AFTERNOON. SPEEDS SHOULD DIMINISH QUICKLY COME THIS EVE. FOG
WILL BE LESS OF A THREAT TONIGHT DUE TO DRYING IN THE LOW-
LEVELS...BUT STILL SOME PATCHY FOG MAY BE SEEN ESPECIALLY IN THOSE
AREAS THAT SAW MORE OF AN APPRECIABLE RAIN DURING THURSDAY /LIKE
RFD/.
MTF
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE THAT BROKEN STRATUS WILL STAY JUST SOUTH OF
MDW.
* MEDIUM CONFIDENCE IN WIND SPEEDS STAY AOB 10KT TODAY.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-MONDAY...VFR.
TUESDAY-WEDNESDAY...VFR AND HOT DURING THE DAYS. SLIGHT CHC OF
STORMS WED NIGHT.
THURSDAY...VFR.
MTF
&&
.MARINE...
306 AM CDT
HIGH PRESSURE WILL EXPAND ITS WAY DOWN THE LAKE TODAY LEADING TO
NORTHEAST WINDS ACROSS NEARSHORE AREAS WHILE DIMINISHING WINDS
OVER THE OPEN WATER. AS THE HIGH DEPARTS OFF TO THE EAST IT WILL
STALL WITH BROAD LOW PRESSURE DEVELOPING OVER THE NORTHERN PLAINS.
THIS PATTERN WILL PERSIST INTO NEXT WEEK MEANING PROLONGED
SOUTHERLY FLOW OVER THE LAKE. SOME 30 KT GUSTS IN THE NORTH ON
SUNDAY COULD BE SEEN. THIS OVERALL WEATHER PATTERN CAN AT TIMES
LEAD TO A STRONG COMPLEX OR TWO OF STORMS FOR THE NORTHERN PART OF
THE LAKE...AND THAT WOULD SEEM MOST FAVORED SOMETIME IN THE MON
NIGHT-WED NIGHT TIME FRAME...THOUGH CONFIDENCE ON THIS REMAINS
LOW. EVENTUALLY THE BROAD LOW WILL SHIFT OVER THE LAKE DURING THE
MIDWEEK PERIOD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ014 UNTIL 7 PM FRIDAY.
IN...BEACH HAZARDS STATEMENT...INZ001 UNTIL 7 PM FRIDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
657 AM CDT Fri Aug 23 2013
.DISCUSSION...
ISSUED 240 AM CDT Fri Aug 23 2013
SHORT TERM...Today through Saturday...
Initial frontal passage has taken place over all of central and
southeast Illinois early this morning, but drier air lingers a bit
further back as lower 60s dew points now starting to enter the far
northern CWA. A cluster of thunderstorms developed from
Springfield to Decatur along the remnants of an old boundary from
earlier, in an area with MUCAPE`s of around 1000 J/kg, and the
cluster has been increasing a bit over the last hour or so as it
moves south-southeast. Latest model guidance suggesting scattered
showers/storms through about mid morning over about the southeast
third of the forecast area.
Further north, fog has been thickening and increasing over the
northeast third of the state, where skies have cleared and the
drier air has arrived. So far visibilities in our area have been
staying up as a band of altocumulus has persisted, but clearing
has been taking place from Galesburg to Lacon. However, the lower
visibilities have been in areas that had quite a bit of rain on
Thursday, and much of our forecast area had a quarter inch or less
except in isolated spots. So, the question is how much of the
forecast area, if any, will see dense fog this morning. HRRR
guidance is the most pessimistic with it fairly widespread along
and north of I-74, while the most recent RAP has scaled back and
went mainly patchy dense fog in the same area. Currently have
mention of 1/2 mile visibility in fog in this area through about 9
am, but will have to monitor for any significant advection from
the northeast.
Once the fog and rain moves out, quiet weather expected through
the first part of the weekend. High pressure drifting through the
Great Lakes will advect some drier air in from the east, but
should still see highs in the mid-upper 80s.
LONG TERM...Sunday through Thursday...
Main weather story over the coming week continues to be with the
expanding heat over the center of the nation, as a large dome of
high pressure aloft drifts eastward. Any MCS ridge riders will be
well to our north, and will continue the dry forecast for next
week. Highs to rise through the 90s much of the week as thermal
ridge builds eastward. Core of this ridge will be in the area on
Wednesday. Latest ECMWF showing upper 90s over most of the
forecast area that day. Have continued to trend temperatures up a
degree or two from blended guidance with mid 90s widespread on
Wednesday. Heat index values of just over 100 likely across the
western CWA Monday-Tuesday and everywhere Wednesday. On Thursday,
the thermal ridge starts shifting westward again, but should still
see highs in the 93-95 range.
Geelhart
&&
.AVIATION...
ISSUED 657 AM CDT Fri Aug 23 2013
Generally quiet/VFR aviation weather conditions expected across
the central Illinois terminals through the 12Z TAF valid time.
Patchy fog/stratus may briefly cause MVFR/IFR conditions for a
couple hours this morning, but otherwise cloud cover should be
minimal. While light fog can not be ruled out overnight tonight,
the drier air filtering into the area around the south side of a
an area high pressure should keep the risk to a minimum.
Bak
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
314 AM CDT FRI AUG 23 2013
.DISCUSSION...
829 PM CDT
A FEW LIGHT SHOWERS CONTINUE TO MOVE SOUTHWARD OUT OF THE EXTREME
SOUTHERN CWA THIS EVENING. SATELLITE IMAGERY AND A LOOK OUT THE
WINDOW SHOWS CLOUDS CLEARING FROM THE NORTHWEST. WINDS HAVE
DIMINISHED ACROSS THE AREA WITH DEWPOINTS REMAINING IN THE MID AND
UPPER 60S. HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST MAINLY TO
ADD FOG MENTION TO MOST AREAS. DRIER AIR WILL SLOWLY FILTER
SOUTHWARD INTO THE AREA TONIGHT BUT THE LIGHT WINDS AND CLEARING
SKIES WILL ALLOW FOR GOOD RADIATIONAL COOLING SO EXPECT SMALL T/TD
SPREADS WITH WET TO EVEN SATURATED GROUND PROMOTING FOG
DEVELOPMENT. SOME OF THIS MAY BE DENSE SO WILL NEED TO MONITOR
TRENDS EARLY TONIGHT FOR A POSSIBLE ADVISORY IF COVERAGE BECOMES
GREAT ENOUGH. THE MAIN AREA OF CONCERN WILL BE INLAND OF THE LAKE
AND ACROSS THE OUTER CHICAGO SUBURBS TO POINTS SOUTH AND WEST. FOG
MAY LINGER PAST DAYBREAK WITH WINDS SLOWLY COMING UP AMID THE
PRESENCE OF HIGH PRESSURE.
MDB
//PREV DISCUSSION...
329 PM CDT
TONIGHT THROUGH FRIDAY NIGHT...CANADIAN HIGH PRESSURE WILL SETTLE
INTO THE GREAT LAKES REGION BEHIND A COLD FRONT. THAT FRONT IS
STILL NOT QUITE THROUGH NORTHERN IL YET. IT IS RIGHT ALONG THE
WI/IL BORDER AT 330 THIS AFTERNOON AND WILL SLOWLY DROP SOUTHWARD
THROUGH THE LOT FORECAST AREA. UNTIL THAT FRONT GETS COMPLETELY
OUT OF THE AREA...THERE WILL BE JUST ENOUGH INSTABILITY AND LOW
LEVEL CONVERGENCE TO KEEP THE MENTION OF A CHANCE FOR SHOWERS IN
THE NORTH AND SHOWERS AND THUNDERSTORMS ROUGHLY SOUTH OF CHICAGO.
THE BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS FROM LATE THIS
AFTERNOON THROUGH LATE EVENING WILL BE IN FAR SOUTHERN LOT FORECAST
AREA WHERE SHORTWAVE ENERGY WILL STILL BE IN THE VICINITY.
DRIER AIR WILL FINALLY SPILL INTO NORTHERN IL AFTER MIDNIGHT AND
HANG AROUND THROUGH FRIDAY AND FRIDAY NIGHT WITH DRY WEATHER.
EXPECTING MUCH MORE SUNSHINE FRIDAY THAN TODAY...SO MAX TEMPS WILL
BE IN THE LOWER 80S...EXCEPT A FEW DEGREES COOLER NEAR THE LAKE WITH
NORTHEAST WINDS.
MRC
SATURDAY AND SUNDAY...SURFACE HIGH PRESSURE SLIDES OVER THE
EASTERN US DURING THIS PERIOD WHILE A 591 TO 594 DM 500 MB HIGH
PRESSURE BUILDS ACROSS THE CENTRAL US. SOME MODELS SHOW A
SHORTWAVE MOVING THROUGH SATURDAY AFTERNOON AND EVENING...BRINGING
A SHOT AT PRECIP. HOWEVER...THE MODELS ARE GENERALLY KEEPING THE
PRECIP TO THE WEST AND NORTHWEST. WILL KEEP THE PRECIP OUT OF THE
FORECAST...AS THE BEST WARM AIR ADVECTION AND COINCIDING Q VECTOR
CONVERGENCE DOES LOOK TO BE TO THE WEST AND NORTHWEST.
THE DRY FORECAST CONTINUES FOR SUNDAY...WITH THE PRECIPITATION
STAYING TO THE NORTH...OVER NORTHERN WISCONSIN...THE UPPER PENINSULA
AND NORTHERN LAKE MICHIGAN.
TEMPS ON SATURDAY WARM A BIT TO THE LOWER TO MID 80S. THEN AT 00Z
ON MONDAY 925 TEMPS REACH ABOUT 23 TO 25 C...BRINGING TEMPS IN THE
UPPER 80S TO AROUND 90 ON SUNDAY.
MONDAY THROUGH THURSDAY...A QUIET AND TOASTY FORECAST IS IN
STORE FOR NEXT WEEK. THE LOWER TO MID 90S LOOK TO STICK AROUND
THROUGH AT LEAST THURSDAY AS THE 500 MB HIGH LINGERS OVER THE
CENTRAL US AND 925 MB TEMPS STAY IN THE UPPER 20S TO AROUND 30 C.
HOWEVER...SOME MODELS CONTINUE TO HINT AT A BACKDOOR COLD FRONT
SLIDING THROUGH WEDNESDAY. THE ECMWF IS CONTINUALLY TRENDING AWAY
FROM THIS THOUGH...SO STICKING WITH THE WARM FORECAST.
TWO PASSING SURFACE LOW PRESSURES COUPLED WITH A FEW WEAK WAVES
RIDING ALONG THE NORTHERN EDGE OF THE 500 MB HIGH WILL BRING PRECIP
CHANCES TO THE NORTH OF ILLINOIS DURING THIS TIME.
MEB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FOG...MAINLY SHALLOW...THROUGH 13Z.
* ENE WINDS AROUND 10 KT LATE THIS MORNING AND AFTERNOON.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS OOZING ITS WAY SOUTHWARD ACROSS THE UPPER MIDWEST
EARLY THIS MORNING. THE LACK OF A STRONG GRADIENT ON ITS LEADING
EDGE AND THE WET GROUND CONDITIONS LOCALLY HAVE ALLOWED FOR FOG
DEVELOPMENT. THIS WILL CONTINUE THROUGH DAYBREAK AND LIKELY AN
HOUR OR SO AFTER. THE FOG IS LIKELY TO BE SHALLOW AT FIRST BUT MAY
SETTLE IN TOWARD DAYBREAK AS THICKER. A SLIGHT NORTHEAST WIND
COMPONENT OFF THE LAKE SHOULD HELP THE PREVAILING VISIBILITY AT
ORD AND MDW REMAIN UP. WINDS WILL PICK UP DURING THE MID TO LATE
MORNING...WITH THE NORTHEAST COMPONENT OFF THE LAKE APPROACHING 10
KT. CLIMATOLOGY POINTS TO THIS BEING CLOSER TO ENE OR EVEN E BY
AFTERNOON. SPEEDS SHOULD DIMINISH QUICKLY IN THE EVE. FOG WILL BE
LESS OF A THREAT FRI NIGHT DUE TO DRYING IN THE LOW-LEVELS...BUT
STILL SOME PATCHY FOG MAY BE SEEN ESPECIALLY IN THOSE AREAS THAT
SAW MORE APPRECIABLE RAIN DURING THURSDAY.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE ON PREVAILING VISIBILITIES REMAINING 5SM OR
GREATER THIS MORNING.
* MEDIUM CONFIDENCE ON WIND SPEEDS ATTAINING 10KT OR HIGHER.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SAT THROUGH WED...VFR. WX NIL.
MTF
&&
.MARINE...
306 AM CDT
HIGH PRESSURE WILL EXPAND ITS WAY DOWN THE LAKE TODAY LEADING TO
NORTHEAST WINDS ACROSS NEARSHORE AREAS WHILE DIMINISHING WINDS
OVER THE OPEN WATER. AS THE HIGH DEPARTS OFF TO THE EAST IT WILL
STALL WITH BROAD LOW PRESSURE DEVELOPING OVER THE NORTHERN PLAINS.
THIS PATTERN WILL PERSIST INTO NEXT WEEK MEANING PROLONGED
SOUTHERLY FLOW OVER THE LAKE. SOME 30 KT GUSTS IN THE NORTH ON
SUNDAY COULD BE SEEN. THIS OVERALL WEATHER PATTERN CAN AT TIMES
LEAD TO A STRONG COMPLEX OR TWO OF STORMS FOR THE NORTHERN PART OF
THE LAKE...AND THAT WOULD SEEM MOST FAVORED SOMETIME IN THE MON
NIGHT-WED NIGHT TIME FRAME...THOUGH CONFIDENCE ON THIS REMAINS
LOW. EVENTUALLY THE BROAD LOW WILL SHIFT OVER THE LAKE DURING THE
MIDWEEK PERIOD.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019-
ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 AM
FRIDAY.
BEACH HAZARDS STATEMENT...ILZ014 UNTIL 9 AM FRIDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 9 AM FRIDAY.
DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9
AM FRIDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
243 AM CDT Fri Aug 23 2013
.DISCUSSION...
ISSUED 240 AM CDT Fri Aug 23 2013
SHORT TERM...Today through Saturday...
Initial frontal passage has taken place over all of central and
southeast Illinois early this morning, but drier air lingers a bit
further back as lower 60s dew points now starting to enter the far
northern CWA. A cluster of thunderstorms developed from
Springfield to Decatur along the remnants of an old boundary from
earlier, in an area with MUCAPE`s of around 1000 J/kg, and the
cluster has been increasing a bit over the last hour or so as it
moves south-southeast. Latest model guidance suggesting scattered
showers/storms through about mid morning over about the southeast
third of the forecast area.
Further north, fog has been thickening and increasing over the
northeast third of the state, where skies have cleared and the
drier air has arrived. So far visibilities in our area have been
staying up as a band of altocumulus has persisted, but clearing
has been taking place from Galesburg to Lacon. However, the lower
visibilities have been in areas that had quite a bit of rain on
Thursday, and much of our forecast area had a quarter inch or less
except in isolated spots. So, the question is how much of the
forecast area, if any, will see dense fog this morning. HRRR
guidance is the most pessimistic with it fairly widespread along
and north of I-74, while the most recent RAP has scaled back and
went mainly patchy dense fog in the same area. Currently have
mention of 1/2 mile visibility in fog in this area through about 9
am, but will have to monitor for any significant advection from
the northeast.
Once the fog and rain moves out, quiet weather expected through
the first part of the weekend. High pressure drifting through the
Great Lakes will advect some drier air in from the east, but
should still see highs in the mid-upper 80s.
LONG TERM...Sunday through Thursday...
Main weather story over the coming week continues to be with the
expanding heat over the center of the nation, as a large dome of
high pressure aloft drifts eastward. Any MCS ridge riders will be
well to our north, and will continue the dry forecast for next
week. Highs to rise through the 90s much of the week as thermal
ridge builds eastward. Core of this ridge will be in the area on
Wednesday. Latest ECMWF showing upper 90s over most of the
forecast area that day. Have continued to trend temperatures up a
degree or two from blended guidance with mid 90s widespread on
Wednesday. Heat index values of just over 100 likely across the
western CWA Monday-Tuesday and everywhere Wednesday. On Thursday,
the thermal ridge starts shifting westward again, but should still
see highs in the 93-95 range.
Geelhart
&&
.AVIATION...
ISSUED 1149 PM CDT Thu Aug 22 2013
A couple of convective updrafts developed along the cold front just
southeast of DEC in the last hour. MLCAPE values of 1000-1500 J/kg
will keep enough elevated instability in place for a few lightning
strikes from the stronger updrafts. Still, coverage will be
isolated and we only included a VCTS for DEC and SPI where the
front will linger the next few hours.
MVFR/IFR fog is expected to develop farther north where skies may
clear out under light winds. BMI/CMI were closer to the rainfall
from early today, so fog formation may become thicker in those
areas. We included tempos for 1SM BR 10-13z, but localized 1/4SM
FG will be possible toward sunrise. PIA fog may dip to IFR, but
the HRRR shows 1/4SM FG for all 3 northern TAF sites between 08z
and 14z. We did not hit fog that hard yet, but will monitor trends
closely.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1253 AM CDT FRI AUG 23 2013
.DISCUSSION...
829 PM CDT
A FEW LIGHT SHOWERS CONTINUE TO MOVE SOUTHWARD OUT OF THE EXTREME
SOUTHERN CWA THIS EVENING. SATELLITE IMAGERY AND A LOOK OUT THE
WINDOW SHOWS CLOUDS CLEARING FROM THE NORTHWEST. WINDS HAVE
DIMINISHED ACROSS THE AREA WITH DEWPOINTS REMAINING IN THE MID AND
UPPER 60S. HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST MAINLY TO
ADD FOG MENTION TO MOST AREAS. DRIER AIR WILL SLOWLY FILTER
SOUTHWARD INTO THE AREA TONIGHT BUT THE LIGHT WINDS AND CLEARING
SKIES WILL ALLOW FOR GOOD RADIATIONAL COOLING SO EXPECT SMALL T/TD
SPREADS WITH WET TO EVEN SATURATED GROUND PROMOTING FOG
DEVELOPMENT. SOME OF THIS MAY BE DENSE SO WILL NEED TO MONITOR
TRENDS EARLY TONIGHT FOR A POSSIBLE ADVISORY IF COVERAGE BECOMES
GREAT ENOUGH. THE MAIN AREA OF CONCERN WILL BE INLAND OF THE LAKE
AND ACROSS THE OUTER CHICAGO SUBURBS TO POINTS SOUTH AND WEST. FOG
MAY LINGER PAST DAYBREAK WITH WINDS SLOWLY COMING UP AMID THE
PRESENCE OF HIGH PRESSURE.
MDB
//PREV DISCUSSION...
329 PM CDT
TONIGHT THROUGH FRIDAY NIGHT...CANADIAN HIGH PRESSURE WILL SETTLE
INTO THE GREAT LAKES REGION BEHIND A COLD FRONT. THAT FRONT IS
STILL NOT QUITE THROUGH NORTHERN IL YET. IT IS RIGHT ALONG THE
WI/IL BORDER AT 330 THIS AFTERNOON AND WILL SLOWLY DROP SOUTHWARD
THROUGH THE LOT FORECAST AREA. UNTIL THAT FRONT GETS COMPLETELY
OUT OF THE AREA...THERE WILL BE JUST ENOUGH INSTABILITY AND LOW
LEVEL CONVERGENCE TO KEEP THE MENTION OF A CHANCE FOR SHOWERS IN
THE NORTH AND SHOWERS AND THUNDERSTORMS ROUGHLY SOUTH OF CHICAGO.
THE BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS FROM LATE THIS
AFTERNOON THROUGH LATE EVENING WILL BE IN FAR SOUTHERN LOT FORECAST
AREA WHERE SHORTWAVE ENERGY WILL STILL BE IN THE VICINITY.
DRIER AIR WILL FINALLY SPILL INTO NORTHERN IL AFTER MIDNIGHT AND
HANG AROUND THROUGH FRIDAY AND FRIDAY NIGHT WITH DRY WEATHER.
EXPECTING MUCH MORE SUNSHINE FRIDAY THAN TODAY...SO MAX TEMPS WILL
BE IN THE LOWER 80S...EXCEPT A FEW DEGREES COOLER NEAR THE LAKE WITH
NORTHEAST WINDS.
MRC
SATURDAY AND SUNDAY...SURFACE HIGH PRESSURE SLIDES OVER THE
EASTERN US DURING THIS PERIOD WHILE A 591 TO 594 DM 500 MB HIGH
PRESSURE BUILDS ACROSS THE CENTRAL US. SOME MODELS SHOW A
SHORTWAVE MOVING THROUGH SATURDAY AFTERNOON AND EVENING...BRINGING
A SHOT AT PRECIP. HOWEVER...THE MODELS ARE GENERALLY KEEPING THE
PRECIP TO THE WEST AND NORTHWEST. WILL KEEP THE PRECIP OUT OF THE
FORECAST...AS THE BEST WARM AIR ADVECTION AND COINCIDING Q VECTOR
CONVERGENCE DOES LOOK TO BE TO THE WEST AND NORTHWEST.
THE DRY FORECAST CONTINUES FOR SUNDAY...WITH THE PRECIPITATION
STAYING TO THE NORTH...OVER NORTHERN WISCONSIN...THE UPPER PENINSULA
AND NORTHERN LAKE MICHIGAN.
TEMPS ON SATURDAY WARM A BIT TO THE LOWER TO MID 80S. THEN AT 00Z
ON MONDAY 925 TEMPS REACH ABOUT 23 TO 25 C...BRINGING TEMPS IN THE
UPPER 80S TO AROUND 90 ON SUNDAY.
MONDAY THROUGH THURSDAY...A QUIET AND TOASTY FORECAST IS IN
STORE FOR NEXT WEEK. THE LOWER TO MID 90S LOOK TO STICK AROUND
THROUGH AT LEAST THURSDAY AS THE 500 MB HIGH LINGERS OVER THE
CENTRAL US AND 925 MB TEMPS STAY IN THE UPPER 20S TO AROUND 30 C.
HOWEVER...SOME MODELS CONTINUE TO HINT AT A BACKDOOR COLD FRONT
SLIDING THROUGH WEDNESDAY. THE ECMWF IS CONTINUALLY TRENDING AWAY
FROM THIS THOUGH...SO STICKING WITH THE WARM FORECAST.
TWO PASSING SURFACE LOW PRESSURES COUPLED WITH A FEW WEAK WAVES
RIDING ALONG THE NORTHERN EDGE OF THE 500 MB HIGH WILL BRING PRECIP
CHANCES TO THE NORTH OF ILLINOIS DURING THIS TIME.
MEB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FOG...MAINLY SHALLOW...THROUGH 13Z.
* ENE WINDS AROUND 10 KT LATE THIS MORNING AND AFTERNOON.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS OOZING ITS WAY SOUTHWARD ACROSS THE UPPER MIDWEST
EARLY THIS MORNING. THE LACK OF A STRONG GRADIENT ON ITS LEADING
EDGE AND THE WET GROUND CONDITIONS LOCALLY HAVE ALLOWED FOR FOG
DEVELOPMENT. THIS WILL CONTINUE THROUGH DAYBREAK AND LIKELY AN
HOUR OR SO AFTER. THE FOG IS LIKELY TO BE SHALLOW AT FIRST BUT MAY
SETTLE IN TOWARD DAYBREAK AS THICKER. A SLIGHT NORTHEAST WIND
COMPONENT OFF THE LAKE SHOULD HELP THE PREVAILING VISIBILITY AT
ORD AND MDW REMAIN UP. WINDS WILL PICK UP DURING THE MID TO LATE
MORNING...WITH THE NORTHEAST COMPONENT OFF THE LAKE APPROACHING 10
KT. CLIMATOLOGY POINTS TO THIS BEING CLOSER TO ENE OR EVEN E BY
AFTERNOON. SPEEDS SHOULD DIMINISH QUICKLY IN THE EVE. FOG WILL BE
LESS OF A THREAT FRI NIGHT DUE TO DRYING IN THE LOW-LEVELS...BUT
STILL SOME PATCHY FOG MAY BE SEEN ESPECIALLY IN THOSE AREAS THAT
SAW MORE APPRECIABLE RAIN DURING THURSDAY.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE ON PREVAILING VISIBILITIES REMAINING 5SM OR
GREATER THIS MORNING.
* MEDIUM CONFIDENCE ON WIND SPEEDS ATTAINING 10KT OR HIGHER.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SAT THROUGH WED...VFR. WX NIL.
MTF
&&
.MARINE...
329 PM CDT
HIGH PRESSURE OF 30.1 INCHES BUILDING ACROSS THE UPPER MIDWEST WILL
SHIFT EAST OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN
LAKES SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES
WILL DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY
AND MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.
NORTH TO NORTHEAST WINDS WILL BUILD HIGHER WAVES IN SOUTHERN LAKE
MICHIGAN THROUGH FRIDAY NIGHT...THEN WINDS WILL SHIFT TO SOUTHERLY
ON SATURDAY AND BUILD HIGHER WAVES OVER THE NORTHERN LAKE ZONES
THROUGH MONDAY NIGHT.
MRC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ014 UNTIL 7 PM FRIDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM FRIDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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Area Forecast Discussion
National Weather Service Lincoln IL
1149 PM CDT Thu Aug 22 2013
.DISCUSSION...
ISSUED 900 PM CDT Thu Aug 22 2013
Showers along the cold front have diminished significantly over
the last hour, and redevelopment the rest of the night will
isolated at best as the front progresses farther south across our
forecast area. We diminished pops to just slights in the east and
south, but confidence is low than any one location will get additional
measurable rain tonight.
Clouds will begin to thin out behind the front per satellite
trends, which will help fog formation across our northern areas
that received rain. We added a mention of some fog for portions of
Marshall county to McLean county...where some of our higher
rainfall totals were.
Temps should have enough time under clearing skies to dip into the
low to mid 60s...while southern areas remain clouded and in the
upper 60s.
Updated the weather and pop grids to the latest trends. The
remainder of the forecast grids were in good shape. Updated info
will be available shortly.
Shimon
&&
.AVIATION...
ISSUED 1149 PM CDT Thu Aug 22 2013
A couple of convective updrafts developed along the cold front just
southeast of dec in the last hour. MLcape values of 1000-1500 J/kg
will keep enough elevated instability in place for a few lightning
strikes from the stronger updrafts. Still, coverage will be
isolated and we only included a vcts for dec and spi where the
front will linger the next few hours.
mvfr/ifr fog is expected to develop farther north where skies may
clear out under light winds. bmi/cmi were closer to the rainfall
from early today...so fog formation may become thicker in those
areas. We included tempos for 1sm br 10-13z, but localized 1/4sm
fg will be possible toward sunrise. PIA fog may dip to ifr, but
the HRRR shows 1/4sm fg for all 3 northern taf sites between 08z
and 14z. We did not hit fog that hard yet, but will monitor trends
closely.
Shimon
&&
.PREV DISCUSSION...
ISSUED 230 PM CDT Thu Aug 22 2013
Forecast problem of today is the convection for tonight, and then
the warming late in the weekend through the middle of next week.
SHORT TERM...Tonight through Saturday night.
Frontal zone over northern IL with upper level wave over eastern
IA to northern MO. Wave triggered convective complex over northern
IL. Airmass over central IL with MUCAPE values around 2500 and
number of outflow boundaries has triggered scattered convection
over north central cwa, with widely scattered convection in the
southeast regions due to the instability. Expect the pcpn to
gradually work its way to the south through evening, and in the
southeast possible overnight.
Boundary should be south of region Friday, and so will be pcpn
free. High pressure to keep air a little drier Saturday.
LONG TERM...Sunday through Thursday.
Upper level ridge start the building process into the our region
Sunday. Southerly surface flow will continue hot and humid air
moving into region, which will continue through mid week. Will
remain dry through forecast period.
Goetsch
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1246 PM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 1240 PM CDT FRI AUG 23 2013
BASED ON TRENDS UP THROUGH MID DAY...THE POTENTIAL FOR ANY DIURNAL
CONVECTION IN THE FAR WEST/SOUTHWEST PARTS OF THE CWFA IS BECOMING
DOUBTFUL.
SATELLITE SHOWS DIURNAL CLOUDS DEVELOPING INDICATING THE BETTER
MOISTURE IS GENERALLY WEST OF THE CWFA. ADDITIONALLY...CONVECTIVE
TEMPERATURES FROM TRENDS IN THE RAP ARE GENERALLY AT OR ABOVE THE
FCST MAX TEMPERATURES FOR THE AFTERNOON. THUS DRY CONDITIONS
SHOULD BE SEEN THIS AFTERNOON AND EVENING. ..08..
UPDATE ISSUED AT 1003 AM CDT FRI AUG 23 2013
THE FOG HAS BURNED OFF AND THE LOW CLOUDS WILL CONTINUE LIFT
THROUGH EARLY AFTERNOON.
RAIN CHANCES DO NOT LOOK OVERLY GREAT FOR THE AFTERNOON HOURS. THE
BETTER MOISTURE LIES JUST WEST OF THE CWFA AS DOES THE PROJECTED
CONVERGENCE. THE EARLY MORNING FOG HAS ALSO STABILIZED THE WESTERN
CWFA SO IT WILL TAKE LONGER TO GENERATE THERMALS. WHAT IS BEING
SUGGESTED BY THE MODELS IS ISOLATED TO PERHAPS VERY LOW END
SCATTERED SHOWERS AND SOME STORMS IN THE EXTREME WESTERN/SOUTHWEST
PARTS OF THE CWFA DURING PEAK HEATING. IF THIS CONVECTION
DEVELOPS...IT WILL DISSIPATE WITH SUNSET. ..08..
&&
.SYNOPSIS...
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE OVER THE SOUTHERN PLAINS DOMINATES THE UPPER PATTERN
THIS MORNING...RESULTING IN WEAK NORTHWEST FLOW OVER THE MIDWEST.
AT THE SURFACE...A WEAK SURFACE FRONT EXTENDS ACROSS NORTHERN
ILLINOIS INTO SOUTHERN IOWA. WIDESPREAD DENSE FOG HAS DEVELOPED
ACROSS MUCH OF THE AREA...MAINLY ALONG AND NORTH OF THE HIGHWAY 20
CORRIDOR IN IOWA AND THEN EAST INTO MUCH OF NORTHERN ILLINOIS WHERE
1+ INCHES OF RAIN FELL YESTERDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN TODAY IS FOG THIS MORNING. GIVEN THE EXTENDED
DRY SPELL OVER MUCH OF THE AREA...EXPECT FOG TO REMAIN CONCENTRATED
IN AREAS WHERE HEAVIER RAIN FELL YESTERDAY. AFTER SUNRISE...MIXING
OF THE BOUNDARY LAYER SHOULD MAKE QUICK WORK OF BURNING OFF THE FOG
AND HAVE ENDED THE ADVISORY AT 9 AM FOR THIS REASON.
ANOTHER MINOR CONCERN IS POSSIBILITY OF SHOWERS THIS AFTERNOON IN
WESTERN PORTIONS OF OUR AREA. SHORT RANGE MODELS INDICATING AN AREA
OF 850MB MOISTURE SURGING UP THROUGH SOUTH CENTRAL AND SOUTHWEST IOWA
THIS AFTERNOON IN THE RETURN FLOW ON THE BACK SIDE OF THE RIDGE. THE
RAP IS FARTHER WEST WITH THE MOIST AXIS THAN THE NAM. GIVEN THE
STRENGTH OF THE LOW LEVEL RIDGE THAT WILL BE IN PLACE OVER THE AREA
THROUGH MID DAY TODAY...THE RAP IS THE MORE LIKELY SOLUTION AND THUS
IS FAVORED. HAVE BACKED OFF ON POPS FOR SOUTHWESTERN SECTIONS OF OUR
AREA THIS AFTERNOON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE BUILDING OVER THE CENTRAL U.S. TO BRING AN EXTENDED
PERIOD OF HOT AND DRY WEATHER THAT WILL DOMINATE MOST OF NEXT WEEK.
THE ONLY SIGNIFICANT CHANCE FOR PRECIPITATION WILL BE SATURDAY...
WHEN A SHORTWAVE TOPPING THE BUILDING UPPER RIDGE MAY INTERACT WITH
THE NORTHWARD ADVANCING WARM FRONT TO PRODUCE MAINLY AFTERNOON
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. EVEN THIS POTENTIAL
LOOKS RATHER LIMITED DUE TO THE WEAK UPPER FORCING AND AXIS OF
PRIMARY LOW LEVEL CONVERGENCE REMAINING WELL WEST OF THE AREA. HAVE
THUS KEPT POPS IN THE SLIGHT CHANCE RANGE. LOW LEVEL SOUTHEAST WINDS
AND CLOUD COVER WILL LIMIT HIGHS TO THE LOWER 80S NORTH...WHILE THE
CENTRAL AND SOUTH SHOULD AGAIN REACH INTO THE MID AND UPPER 80S.
SUNDAY THROUGH THURSDAY...HEAT BUILDS OVER THE AREA AS HIGH PRESSURE
AT 500 MB SETS UP OVER KS AND MOVES VERY LITTLE THROUGH THE WEEK.
OVERALL...THE SYNOPTIC SETUP IS TYPICAL FOR A MID TO LATE SUMMER
HEAT WAVE IN THE REGION THAT OFTEN RESULT IN 100 DEGREE PLUS
TEMPERATURES WHEN THEY OCCUR IN JULY OR EARLY AUGUST. FOR
NOW...WILL NOT FORECAST TEMPERATURES THAT WARM BUT MAY STILL SEE
SOME RECORD HIGHS. 850 MB TEMPERATURES ARE SHOWN RISING TO 22 TO 24
C RANGE BY WED...SUPPORTING HIGH TEMPERATURES WELL INTO THE 90S.
SUNDAY WILL BE THE COOLEST OF THE STRETCH WITH 850 MB TEMPERATURES
SIMILAR TO THE SETUP A COUPLE DAYS AGO THAT RESULTED IN TEMPERATURES
TOPPING OUT IN THE UPPER 80S TO AROUND 90.
MODELS BEGIN TO DIVERGE ON WED...WHEN THE ECMWF HAS A FLATTER RIDGE
THAT MAY ALLOW THE SURFACE BOUNDARY TO SAG BACK SOUTH INTO THE
FORECAST AREA...WHICH WOULD RESULT IN COOLER TEMPERATURES AND
POSSIBLE RAIN CHANCES. FOR NOW...THE OVERALL MODEL CONSENSUS WILL
KEEP A DRY FORECAST WITH HIGHS IN THE LOWER TO MID 90S MON THROUGH
THU.
HEAT INDEX READINGS WILL OF COURSE BE MUCH HIGHER AND LIKELY REACH
ABOVE 100 AND A HEAT ADVISORY MAY BE NEEDED FOR MON THROUGH THU.
THESE HEAT INDEX VALUES WILL BE GREATLY DEPENDENT ON DEW POINTS...
WHICH ARE OF BELOW AVERAGE CONFIDENCE DUE TO HOW MODELS HANDLE
MIXING AND WHETHER THEY EFFECTIVELY CAPTURE THE INCREASINGLY DRY
SURFACE CONDITIONS IN PLACE OVER ALL BUT THE NORTHERN THIRD AND FAR
EASTERN PORTIONS OF THE FORECAST AREA THAT SAW RAIN THURSDAY. WILL
CONTINUE TO MENTION THE EXCESSIVE LATE SEASON HEAT AND POSSIBLE NEED
FOR AN ADVISORY IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM CDT FRI AUG 23 2013
VFR WX IS EXPECTED THROUGH 06Z/24 AS HIGH PRESSURE REMAINS OVER
THE GREAT LAKES. AFT 06Z/24 INCREASING LOW LEVEL MOISTURE SHOULD
ALLOW MVFR VSBYS TO DEVELOP PRIOR TO SUNRISE. AFT SUNRISE SATURDAY
CONDITIONS WILL AGAIN IMPROVE TO VFR. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1008 AM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 1003 AM CDT FRI AUG 23 2013
THE FOG HAS BURNED OFF AND THE LOW CLOUDS WILL CONTINUE LIFT
THROUGH EARLY AFTERNOON.
RAIN CHANCES DO NOT LOOK OVERLY GREAT FOR THE AFTERNOON HOURS. THE
BETTER MOISTURE LIES JUST WEST OF THE CWFA AS DOES THE PROJECTED
CONVERGENCE. THE EARLY MORNING FOG HAS ALSO STABILIZED THE WESTERN
CWFA SO IT WILL TAKE LONGER TO GENERATE THERMALS. WHAT IS BEING
SUGGESTED BY THE MODELS IS ISOLATED TO PERHAPS VERY LOW END
SCATTERED SHOWERS AND SOME STORMS IN THE EXTREME WESTERN/SOUTHWEST
PARTS OF THE CWFA DURING PEAK HEATING. IF THIS CONVECTION
DEVELOPS...IT WILL DISSIPATE WITH SUNSET. ..08..
&&
.SYNOPSIS...
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE OVER THE SOUTHERN PLAINS DOMINATES THE UPPER PATTERN
THIS MORNING...RESULTING IN WEAK NORTHWEST FLOW OVER THE MIDWEST.
AT THE SURFACE...A WEAK SURFACE FRONT EXTENDS ACROSS NORTHERN
ILLINOIS INTO SOUTHERN IOWA. WIDESPREAD DENSE FOG HAS DEVELOPED
ACROSS MUCH OF THE AREA...MAINLY ALONG AND NORTH OF THE HIGHWAY 20
CORRIDOR IN IOWA AND THEN EAST INTO MUCH OF NORTHERN ILLINOIS WHERE
1+ INCHES OF RAIN FELL YESTERDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN TODAY IS FOG THIS MORNING. GIVEN THE EXTENDED
DRY SPELL OVER MUCH OF THE AREA...EXPECT FOG TO REMAIN CONCENTRATED
IN AREAS WHERE HEAVIER RAIN FELL YESTERDAY. AFTER SUNRISE...MIXING
OF THE BOUNDARY LAYER SHOULD MAKE QUICK WORK OF BURNING OFF THE FOG
AND HAVE ENDED THE ADVISORY AT 9 AM FOR THIS REASON.
ANOTHER MINOR CONCERN IS POSSIBILITY OF SHOWERS THIS AFTERNOON IN
WESTERN PORTIONS OF OUR AREA. SHORT RANGE MODELS INDICATING AN AREA
OF 850MB MOISTURE SURGING UP THROUGH SOUTH CENTRAL AND SOUTHWEST IOWA
THIS AFTERNOON IN THE RETURN FLOW ON THE BACK SIDE OF THE RIDGE. THE
RAP IS FARTHER WEST WITH THE MOIST AXIS THAN THE NAM. GIVEN THE
STRENGTH OF THE LOW LEVEL RIDGE THAT WILL BE IN PLACE OVER THE AREA
THROUGH MID DAY TODAY...THE RAP IS THE MORE LIKELY SOLUTION AND THUS
IS FAVORED. HAVE BACKED OFF ON POPS FOR SOUTHWESTERN SECTIONS OF OUR
AREA THIS AFTERNOON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE BUILDING OVER THE CENTRAL U.S. TO BRING AN EXTENDED
PERIOD OF HOT AND DRY WEATHER THAT WILL DOMINATE MOST OF NEXT WEEK.
THE ONLY SIGNIFICANT CHANCE FOR PRECIPITATION WILL BE SATURDAY...
WHEN A SHORTWAVE TOPPING THE BUILDING UPPER RIDGE MAY INTERACT WITH
THE NORTHWARD ADVANCING WARM FRONT TO PRODUCE MAINLY AFTERNOON
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. EVEN THIS POTENTIAL
LOOKS RATHER LIMITED DUE TO THE WEAK UPPER FORCING AND AXIS OF
PRIMARY LOW LEVEL CONVERGENCE REMAINING WELL WEST OF THE AREA. HAVE
THUS KEPT POPS IN THE SLIGHT CHANCE RANGE. LOW LEVEL SOUTHEAST WINDS
AND CLOUD COVER WILL LIMIT HIGHS TO THE LOWER 80S NORTH...WHILE THE
CENTRAL AND SOUTH SHOULD AGAIN REACH INTO THE MID AND UPPER 80S.
SUNDAY THROUGH THURSDAY...HEAT BUILDS OVER THE AREA AS HIGH PRESSURE
AT 500 MB SETS UP OVER KS AND MOVES VERY LITTLE THROUGH THE WEEK.
OVERALL...THE SYNOPTIC SETUP IS TYPICAL FOR A MID TO LATE SUMMER
HEAT WAVE IN THE REGION THAT OFTEN RESULT IN 100 DEGREE PLUS
TEMPERATURES WHEN THEY OCCUR IN JULY OR EARLY AUGUST. FOR
NOW...WILL NOT FORECAST TEMPERATURES THAT WARM BUT MAY STILL SEE
SOME RECORD HIGHS. 850 MB TEMPERATURES ARE SHOWN RISING TO 22 TO 24
C RANGE BY WED...SUPPORTING HIGH TEMPERATURES WELL INTO THE 90S.
SUNDAY WILL BE THE COOLEST OF THE STRETCH WITH 850 MB TEMPERATURES
SIMILAR TO THE SETUP A COUPLE DAYS AGO THAT RESULTED IN TEMPERATURES
TOPPING OUT IN THE UPPER 80S TO AROUND 90.
MODELS BEGIN TO DIVERGE ON WED...WHEN THE ECMWF HAS A FLATTER RIDGE
THAT MAY ALLOW THE SURFACE BOUNDARY TO SAG BACK SOUTH INTO THE
FORECAST AREA...WHICH WOULD RESULT IN COOLER TEMPERATURES AND
POSSIBLE RAIN CHANCES. FOR NOW...THE OVERALL MODEL CONSENSUS WILL
KEEP A DRY FORECAST WITH HIGHS IN THE LOWER TO MID 90S MON THROUGH
THU.
HEAT INDEX READINGS WILL OF COURSE BE MUCH HIGHER AND LIKELY REACH
ABOVE 100 AND A HEAT ADVISORY MAY BE NEEDED FOR MON THROUGH THU.
THESE HEAT INDEX VALUES WILL BE GREATLY DEPENDENT ON DEW POINTS...
WHICH ARE OF BELOW AVERAGE CONFIDENCE DUE TO HOW MODELS HANDLE
MIXING AND WHETHER THEY EFFECTIVELY CAPTURE THE INCREASINGLY DRY
SURFACE CONDITIONS IN PLACE OVER ALL BUT THE NORTHERN THIRD AND FAR
EASTERN PORTIONS OF THE FORECAST AREA THAT SAW RAIN THURSDAY. WILL
CONTINUE TO MENTION THE EXCESSIVE LATE SEASON HEAT AND POSSIBLE NEED
FOR AN ADVISORY IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI AUG 23 2013
PATCHY DENSE FOG IS AFFECTING AREA TAF SITES THIS MORNING WITH
MOST EXPERIENCING IFR OR LIFR CONDITIONS. FOG WILL LIFT RAPIDLY WITHIN THE
NEXT 2 HOURS AS THE RISING SUN BEGINS TO PERCOLATE THE BOUNDARY
LAYER. ONCE THE FOG LIFTS...EXPECT VFR CONDITIONS WITH SCATTERED
AFTERNOON CUMULUS ABOVE 3000FT. OTHERWISE...LIGHT SURFACE WINDS
WILL SHIFT TO THE EAST THEN SOUTHEAST THROUGH THE DAY AS THE
SURFACE HIGH PRESSURE RIDGE SLIDES EASTWARD ACROSS THE GREAT LAKES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
641 AM CDT FRI AUG 23 2013
.SYNOPSIS...
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE OVER THE SOUTHERN PLAINS DOMINATES THE UPPER PATTERN
THIS MORNING...RESULTING IN WEAK NORTHWEST FLOW OVER THE MIDWEST.
AT THE SURFACE...A WEAK SURFACE FRONT EXTENDS ACROSS NORTHERN
ILLINOIS INTO SOUTHERN IOWA. WIDESPREAD DENSE FOG HAS DEVELOPED
ACROSS MUCH OF THE AREA...MAINLY ALONG AND NORTH OF THE HIGHWAY 20
CORRIDOR IN IOWA AND THEN EAST INTO MUCH OF NORTHERN ILLINOIS WHERE
1+ INCHES OF RAIN FELL YESTERDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN TODAY IS FOG THIS MORNING. GIVEN THE EXTENDED
DRY SPELL OVER MUCH OF THE AREA...EXPECT FOG TO REMAIN CONCENTRATED
IN AREAS WHERE HEAVIER RAIN FELL YESTERDAY. AFTER SUNRISE...MIXING
OF THE BOUNDARY LAYER SHOULD MAKE QUICK WORK OF BURNING OFF THE FOG
AND HAVE ENDED THE ADVISORY AT 9 AM FOR THIS REASON.
ANOTHER MINOR CONCERN IS POSSIBILITY OF SHOWERS THIS AFTERNOON IN
WESTERN PORTIONS OF OUR AREA. SHORT RANGE MODELS INDICATING AN AREA
OF 850MB MOISTURE SURGING UP THROUGH SOUTH CENTRAL AND SOUTHWEST IOWA
THIS AFTERNOON IN THE RETURN FLOW ON THE BACK SIDE OF THE RIDGE. THE
RAP IS FARTHER WEST WITH THE MOIST AXIS THAN THE NAM. GIVEN THE
STRENGTH OF THE LOW LEVEL RIDGE THAT WILL BE IN PLACE OVER THE AREA
THROUGH MID DAY TODAY...THE RAP IS THE MORE LIKELY SOLUTION AND THUS
IS FAVORED. HAVE BACKED OFF ON POPS FOR SOUTHWESTERN SECTIONS OF OUR
AREA THIS AFTERNOON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE BUILDING OVER THE CENTRAL U.S. TO BRING AN EXTENDED
PERIOD OF HOT AND DRY WEATHER THAT WILL DOMINATE MOST OF NEXT WEEK.
THE ONLY SIGNIFICANT CHANCE FOR PRECIPITATION WILL BE SATURDAY...
WHEN A SHORTWAVE TOPPING THE BUILDING UPPER RIDGE MAY INTERACT WITH
THE NORTHWARD ADVANCING WARM FRONT TO PRODUCE MAINLY AFTERNOON
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. EVEN THIS POTENTIAL
LOOKS RATHER LIMITED DUE TO THE WEAK UPPER FORCING AND AXIS OF
PRIMARY LOW LEVEL CONVERGENCE REMAINING WELL WEST OF THE AREA. HAVE
THUS KEPT POPS IN THE SLIGHT CHANCE RANGE. LOW LEVEL SOUTHEAST WINDS
AND CLOUD COVER WILL LIMIT HIGHS TO THE LOWER 80S NORTH...WHILE THE
CENTRAL AND SOUTH SHOULD AGAIN REACH INTO THE MID AND UPPER 80S.
SUNDAY THROUGH THURSDAY...HEAT BUILDS OVER THE AREA AS HIGH PRESSURE
AT 500 MB SETS UP OVER KS AND MOVES VERY LITTLE THROUGH THE WEEK.
OVERALL...THE SYNOPTIC SETUP IS TYPICAL FOR A MID TO LATE SUMMER
HEAT WAVE IN THE REGION THAT OFTEN RESULT IN 100 DEGREE PLUS
TEMPERATURES WHEN THEY OCCUR IN JULY OR EARLY AUGUST. FOR
NOW...WILL NOT FORECAST TEMPERATURES THAT WARM BUT MAY STILL SEE
SOME RECORD HIGHS. 850 MB TEMPERATURES ARE SHOWN RISING TO 22 TO 24
C RANGE BY WED...SUPPORTING HIGH TEMPERATURES WELL INTO THE 90S.
SUNDAY WILL BE THE COOLEST OF THE STRETCH WITH 850 MB TEMPERATURES
SIMILAR TO THE SETUP A COUPLE DAYS AGO THAT RESULTED IN TEMPERATURES
TOPPING OUT IN THE UPPER 80S TO AROUND 90.
MODELS BEGIN TO DIVERGE ON WED...WHEN THE ECMWF HAS A FLATTER RIDGE
THAT MAY ALLOW THE SURFACE BOUNDARY TO SAG BACK SOUTH INTO THE
FORECAST AREA...WHICH WOULD RESULT IN COOLER TEMPERATURES AND
POSSIBLE RAIN CHANCES. FOR NOW...THE OVERALL MODEL CONSENSUS WILL
KEEP A DRY FORECAST WITH HIGHS IN THE LOWER TO MID 90S MON THROUGH
THU.
HEAT INDEX READINGS WILL OF COURSE BE MUCH HIGHER AND LIKELY REACH
ABOVE 100 AND A HEAT ADVISORY MAY BE NEEDED FOR MON THROUGH THU.
THESE HEAT INDEX VALUES WILL BE GREATLY DEPENDENT ON DEW POINTS...
WHICH ARE OF BELOW AVERAGE CONFIDENCE DUE TO HOW MODELS HANDLE
MIXING AND WHETHER THEY EFFECTIVELY CAPTURE THE INCREASINGLY DRY
SURFACE CONDITIONS IN PLACE OVER ALL BUT THE NORTHERN THIRD AND FAR
EASTERN PORTIONS OF THE FORECAST AREA THAT SAW RAIN THURSDAY. WILL
CONTINUE TO MENTION THE EXCESSIVE LATE SEASON HEAT AND POSSIBLE NEED
FOR AN ADVISORY IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI AUG 23 2013
PATCHY DENSE FOG IS AFFECTING AREA TAF SITES THIS MORNING WITH
MOST EXPERIENCING IFR OR LIFR CONDITIONS. FOG WILL LIFT RAPIDLY WITHIN THE
NEXT 2 HOURS AS THE RISING SUN BEGINS TO PERCOLATE THE BOUNDARY
LAYER. ONCE THE FOG LIFTS...EXPECT VFR CONDITIONS WITH SCATTERED
AFTERNOON CUMULUS ABOVE 3000FT. OTHERWISE...LIGHT SURFACE WINDS
WILL SHIFT TO THE EAST THEN SOUTHEAST THROUGH THE DAY AS THE
SURFACE HIGH PRESSURE RIDGE SLIDES EASTWARD ACROSS THE GREAT LAKES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-LINN-
SCOTT.
IL...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BUREAU-
CARROLL-HENRY IL-JO DAVIESS-PUTNAM-ROCK ISLAND-STEPHENSON-
WHITESIDE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
319 AM CDT FRI AUG 23 2013
.SYNOPSIS...
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE OVER THE SOUTHERN PLAINS DOMINATES THE UPPER PATTERN
THIS MORNING...RESULTING IN WEAK NORTHWEST FLOW OVER THE MIDWEST.
AT THE SURFACE...A WEAK SURFACE FRONT EXTENDS ACROSS NORTHERN
ILLINOIS INTO SOUTHERN IOWA. WIDESPREAD DENSE FOG HAS DEVELOPED
ACROSS MUCH OF THE AREA...MAINLY ALONG AND NORTH OF THE HIGHWAY 20
CORRIDOR IN IOWA AND THEN EAST INTO MUCH OF NORTHERN ILLINOIS WHERE
1+ INCHES OF RAIN FELL YESTERDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN TODAY IS FOG THIS MORNING. GIVEN THE EXTENDED
DRY SPELL OVER MUCH OF THE AREA...EXPECT FOG TO REMAIN CONCENTRATED
IN AREAS WHERE HEAVIER RAIN FELL YESTERDAY. AFTER SUNRISE...MIXING
OF THE BOUNDARY LAYER SHOULD MAKE QUICK WORK OF BURNING OFF THE FOG
AND HAVE ENDED THE ADVISORY AT 9 AM FOR THIS REASON.
ANOTHER MINOR CONCERN IS POSSIBILITY OF SHOWERS THIS AFTERNOON IN
WESTERN PORTIONS OF OUR AREA. SHORT RANGE MODELS INDICATING AN AREA
OF 850MB MOISTURE SURGING UP THROUGH SOUTH CENTRAL AND SOUTHWEST IOWA
THIS AFTERNOON IN THE RETURN FLOW ON THE BACK SIDE OF THE RIDGE. THE
RAP IS FARTHER WEST WITH THE MOIST AXIS THAN THE NAM. GIVEN THE
STRENGTH OF THE LOW LEVEL RIDGE THAT WILL BE IN PLACE OVER THE AREA
THROUGH MID DAY TODAY...THE RAP IS THE MORE LIKELY SOLUTION AND THUS
IS FAVORED. HAVE BACKED OFF ON POPS FOR SOUTHWESTERN SECTIONS OF OUR
AREA THIS AFTERNOON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 23 2013
UPPER RIDGE BUILDING OVER THE CENTRAL U.S. TO BRING AN EXTENDED
PERIOD OF HOT AND DRY WEATHER THAT WILL DOMINATE MOST OF NEXT WEEK.
THE ONLY SIGNIFICANT CHANCE FOR PRECIPITATION WILL BE SATURDAY...
WHEN A SHORTWAVE TOPPING THE BUILDING UPPER RIDGE MAY INTERACT WITH
THE NORTHWARD ADVANCING WARM FRONT TO PRODUCE MAINLY AFTERNOON
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. EVEN THIS POTENTIAL
LOOKS RATHER LIMITED DUE TO THE WEAK UPPER FORCING AND AXIS OF
PRIMARY LOW LEVEL CONVERGENCE REMAINING WELL WEST OF THE AREA. HAVE
THUS KEPT POPS IN THE SLIGHT CHANCE RANGE. LOW LEVEL SOUTHEAST WINDS
AND CLOUD COVER WILL LIMIT HIGHS TO THE LOWER 80S NORTH...WHILE THE
CENTRAL AND SOUTH SHOULD AGAIN REACH INTO THE MID AND UPPER 80S.
SUNDAY THROUGH THURSDAY...HEAT BUILDS OVER THE AREA AS HIGH PRESSURE
AT 500 MB SETS UP OVER KS AND MOVES VERY LITTLE THROUGH THE WEEK.
OVERALL...THE SYNOPTIC SETUP IS TYPICAL FOR A MID TO LATE SUMMER
HEAT WAVE IN THE REGION THAT OFTEN RESULT IN 100 DEGREE PLUS
TEMPERATURES WHEN THEY OCCUR IN JULY OR EARLY AUGUST. FOR
NOW...WILL NOT FORECAST TEMPERATURES THAT WARM BUT MAY STILL SEE
SOME RECORD HIGHS. 850 MB TEMPERATURES ARE SHOWN RISING TO 22 TO 24
C RANGE BY WED...SUPPORTING HIGH TEMPERATURES WELL INTO THE 90S.
SUNDAY WILL BE THE COOLEST OF THE STRETCH WITH 850 MB TEMPERATURES
SIMILAR TO THE SETUP A COUPLE DAYS AGO THAT RESULTED IN TEMPERATURES
TOPPING OUT IN THE UPPER 80S TO AROUND 90.
MODELS BEGIN TO DIVERGE ON WED...WHEN THE ECMWF HAS A FLATTER RIDGE
THAT MAY ALLOW THE SURFACE BOUNDARY TO SAG BACK SOUTH INTO THE
FORECAST AREA...WHICH WOULD RESULT IN COOLER TEMPERATURES AND
POSSIBLE RAIN CHANCES. FOR NOW...THE OVERALL MODEL CONSENSUS WILL
KEEP A DRY FORECAST WITH HIGHS IN THE LOWER TO MID 90S MON THROUGH
THU.
HEAT INDEX READINGS WILL OF COURSE BE MUCH HIGHER AND LIKELY REACH
ABOVE 100 AND A HEAT ADVISORY MAY BE NEEDED FOR MON THROUGH THU.
THESE HEAT INDEX VALUES WILL BE GREATLY DEPENDENT ON DEWPOINTS...
WHICH ARE OF BELOW AVERAGE CONFIDENCE DUE TO HOW MODELS HANDLE
MIXING AND WHETHER THEY EFFECTIVELY CAPTURE THE INCREASINGLY DRY
SURFACE CONDITIONS IN PLACE OVER ALL BUT THE NORTHERN THIRD AND FAR
EASTERN PORTIONS OF THE FORECAST AREA THAT SAW RAIN THURSDAY. WILL
CONTINUE TO MENTION THE EXCESSIVE LATE SEASON HEAT AND POSSIBLE NEED
FOR AN ADVISORY IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1145 PM CDT THU AUG 22 2013
ABUNDANT LOW LEVEL MOISTURE...MAINLY CLEAR SKIES AND LIGHT WINDS WILL
CONTINUE TO PROMOTE SOME STRATUS AND FOG DEVELOPMENT OVERNIGHT
UNTIL MID MORNING. SHALLOW STEEP LOW LEVEL INVERSION SUPPORTIVE OF
VSBYS BEING QUITE VARIABLE 1-5SM... WITH SOME PATCHY 1/4-1/2SM.
HAVE CONTINUED WITH THE LOWEST VSBYS OF LIFR AT KDBQ DUE TO WET
GROUND FROM RECENT RAINS. CANT RULE OUT VLIFR THOUGH AT KDBQ...
AND SOME OF THE LATEST HI-RES GUIDANCE CONTINUES TO SUGGEST
LIFR/VLIFR MORE WIDESPREAD ALSO AFFECTING KCID...KMLI AND KBRL BUT
HELD OFF ON MENTION AT THESE TAF SITES DUE TO LOWER CONFIDENCE.
ALSO...AREAS OF MVFR CIGS MOST PREVALENT AT KBRL OVERNIGHT WHERE
THE HIGHER SURFACE DEWPTS ARE LOCATED. COULD SEE A BRIEF PERIOD OF
MVFR CIGS AT ALL SITES DEVELOP BY MID MORNING WITH HEATING OF
LOW LEVEL MOISTURE...BUT ANY LOW CLOUDS AND FOG TO LIFT BY 18Z
WITH VFR CONDITIONS THEREAFTER AS WINDS INCREASE FROM THE E/SE AT
5-10 KTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BUCHANAN-
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES.
IL...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BUREAU-
CARROLL-JO DAVIESS-PUTNAM-STEPHENSON-WHITESIDE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...05
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
549 PM CDT Fri Aug 23 2013
...Updated for Aviation...
.SYNOPSIS...
ISSUED AT 1208 PM CDT FRI AUG 23 2013
At 12z Friday a 500mb trough was located over northern California
and the pacific northwest. A 500mb high was located across western
Oklahoma. An upper level ridge axis extended from this upper high
northward into south central Canada. 700mb temperatures at 12z
this morning across the central high plains ranged from 11c at
Dodge City and North Platte to +16c at Denver. A 850mb BAROCLINIC
zone extended from southwest Nebraska to northeast Oklahoma.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 202 PM CDT FRI AUG 23 2013
Water Vapor loop indicating an upper level disturbance was moving
north across east central Colorado earlier this morning. The 12z
RAP, NAM,and GFS 400-450mb potential vorticity field picked up on
this feature fairly well and currently moves this feature across
northern Kansas early this evening. NAM and to a lesser degree RAP
and HRRR even hints at some precipitation this evening near and
north of I70 as this wave passes. Given the late day instability
expected ahead of this wave the chance for an isolated
thunderstorm or two can not be ruled out...especially near the
Nebraska border. At this time am leaning towards leaving mention
of thunderstorms out of the forecast near the interstate 70
corridor given the better instability and forcing is forecast to
be further north. Will however insert a mention of isolated
thunderstorms if convection appears to be developing further south
than anticipated.
Skies are expected to clear from west to east as this upper wave
passes north central Kansas after midnight. Given surface
dewpoints in the 60s and surface winds at 10kts will stay close
to the previous forecast with overnight ranging from the mid 60s
in far western Kansas to around 70 in north central and south
central Kansas.
On Saturday an upper high will slowly move east across southwest
Kansas and 800mb temperatures at 00z Sunday are forecast range
from 24c to 28c. This suggests highs Saturday afternoon mainly in
the mid 90s given full sun.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 340 PM CDT FRI AUG 23 2013
The medium range forecast models continue to develop a large broad
upper height ridge across the central section of the nation through
next weekend. This will promote large scale subsidence aloft and
southerly surface winds across western Kansas. Although technically
not zero percent, very little chance for convection is expected
during this period. The only opportunity for convection would be
late evening or overnight near the Colorado line as localized high
terrain convection can feed on steep mid level lapse rates far
enough east. The flow however doesn`t support this. Beside the lack
of precipitation, the period will be marked by a few breezy to
marginally windy days and very warm conditions. High surface
pressure across the eastern states will setup a pressure gradient to
the lee of the Rockies creating diurnally mixed out gusty south winds.
The models in addition to the MOS products have trended temperatures
warmer in recent runs. Highs during the period will likely be at
least 5 degrees to as much as 10 degrees warmer than normal.
Persistence or intensification of the drought conditions are
expected to the west of highway 283.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 545 PM CDT FRI AUG 23 2013
VFR conditions will continue into Saturday with light south to
southeast winds increasing to 15-25kt after 15-17Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 95 72 96 / 0 0 0 0
GCK 67 96 71 96 / 0 0 0 0
EHA 66 94 70 94 / 0 0 0 0
LBL 66 96 72 96 / 0 0 0 0
HYS 70 96 72 97 / 10 0 0 0
P28 71 95 73 96 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Russell
AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
341 PM CDT Fri Aug 23 2013
...UPDATED LONG TERM...
.SYNOPSIS...
ISSUED AT 1208 PM CDT FRI AUG 23 2013
At 12z Friday a 500mb trough was located over northern California
and the pacific northwest. A 500mb high was located across western
Oklahoma. An upper level ridge axis extended from this upper high
northward into south central Canada. 700mb temperatures at 12z
this morning across the central high plains ranged from 11c at
Dodge City and North Platte to +16c at Denver. A 850mb baroclinic
zone extended from southwest Nebraska to northeast Oklahoma.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 202 PM CDT FRI AUG 23 2013
Water Vapor loop indicating an upper level disturbance was moving
north across east central Colorado earlier this morning. The 12z
RAP, NAM,and GFS 400-450mb potential vorticity field picked up on
this feature fairly well and currently moves this feature across
northern Kansas early this evening. NAM and to a lesser degree RAP
and HRRR even hints at some precipitation this evening near and
north of I70 as this wave passes. Given the late day instability
expected ahead of this wave the chance for an isolated
thunderstorm or two can not be ruled out...especially near the
Nebraska border. At this time am leaning towards leaving mention
of thunderstorms out of the forecast near the interstate 70
corridor given the better instability and forcing is forecast to
be further north. Will however insert a mention of isolated
thunderstorms if convection appears to be developing further south
than anticipated.
Skies are expected to clear from west to east as this upper wave
passes north central Kansas after midnight. Given surface
dewpoints in the 60s and surface winds at 10kts will stay close to
the previous forecast with overnight ranging from the mid 60s in
far western Kansas to around 70 in north central and south central
Kansas.
On Saturday an upper high will slowly move east across southwest
Kansas and 800mb temperatures at 00z Sunday are forecast range
from 24c to 28c. This suggests highs Saturday afternoon mainly in
the mid 90s given full sun.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 340 PM CDT FRI AUG 23 2013
The medium range forecast models continue to develop a large broad
upper height ridge across the central section of the nation through
next weekend. This will promote large scale subsidence aloft and
southerly surface winds across western Kansas. Although technically
not zero percent, very little chance for convection is expected
during this period. The only opportunity for convection would be
late evening or overnight near the Colorado line as localized high
terrain convection can feed on steep mid level lapse rates far
enough east. The flow however doesn`t support this. Beside the lack
of precipitation, the period will be marked by a few breezy to
marginally windy days and very warm conditions. High surface
pressure across the eastern states will setup a pressure gradient to
the lee of the Rockies creating diurnally mixed out gusty south winds.
The models in addition to the MOS products have trended temperatures
warmer in recent runs. Highs during the period will likely be at
least 5 degrees to as much as 10 degrees warmer than normal.
Persistence or intensification of the drought conditions are
expected to the west of highway 283.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1208 PM CDT FRI AUG 23 2013
VFR conditions can be expected through tonight at all TAF sites. As
surface troughing persist on the lee side of the Rockies, winds will
remain southerly this afternoon and evening from 10 to 15 kt. A few
gusts around 25 kt could be possible this afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 95 72 96 / 0 0 0 0
GCK 67 96 71 96 / 0 0 0 0
EHA 66 94 70 94 / 0 0 0 0
LBL 66 96 72 96 / 0 0 0 0
HYS 70 96 72 97 / 10 0 0 0
P28 71 95 73 96 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Russell
AVIATION...Scott
AREA FORECAST DISCUSSION
NWS GOODLAND KS
158 PM MDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 559 AM MDT FRI AUG 23 2013
JUST FINISHED QUICK UPDATE TO POP/WX TO REFLECT CURRENT COVERAGE
OF SHOWERS/THUNDERSTORMS IN EASTER CWA. ALSO LINGERING SLIGHT
CHANCE POPS IN NORTHERN CWA THROUGH DAY TO ACCOUNT FOR POSSIBLE
SHOWERS/THUNDERSTORMS REDEVELOPING AS MESO-LOW FROM OVERNIGHT
CONVECTION OVER NE COLORADO SLOWLY MOVES OVER CWA. THERE APPEARS
TO BE SOME REFLECTION AT H7-H5 FROM RAP WITH THIS FEATURE. LATEST
HRRR WOULD ACTUALLY SUPPORT BETTER COVERAGE AFTER
SUNRISE...HOWEVER WITH VERY LITTLE RETURNS YET THIS MORNING WILL
STAY CONSERVATIVE WITH THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 251 AM MDT FRI AUG 23 2013
LATEST WV IMAGERY AND H5 ANALYSIS SHOWS LARGE SCALE RIDGE OVER
THE CENTRAL US...CENTERED OVER THE SOUTHERN PLAINS. A STALLED
FRONT EXTENDS SOUTH ALONG THE FRONT RANGE IN COLORADO AND BACK TO
THE EAST AS A WARM FRONT OVER THE SOUTHERN HALF OF OUR CWA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY
THIS MORNING ACROSS OUR CWA AS A WARM FRONT HAS LIFTED NORTH WITH
GOOD MOISTURE AND MARGINAL INSTABILITY IN PLACE...AND SUPPORT FROM
LLJ/MID LEVEL THETA-E CONVERGENCE. SHORT RANGE GUIDANCE HAS DECENT
HANDLE ON SHOWERS/THUNDERSTORMS IN EASTERN COLORADO...HOWEVER IS
NOT DOING A GOOD JOB WITH ACTIVITY ALONG FRONT ACROSS REST OF CWA.
WHILE CHANCE OF MEASURABLE IS NOT AS GREAT...COVERAGE ON RADAR HAS
INCREASED QUITE A BIT OVER THE LAST FEW HOURS...SO I WENT AHEAD
AND INCREASE POPS TO CHANCE CATEGORY. IVE TRENDED THIS ACTIVITY
NORTHWARD THROUGH SUNRISE BASED ON TIMING OF FRONT. I COULD NT
RULE OUT ACTIVITY POSSIBLY LINGERING THROUGH MID MORNING...HOWEVER
IT APPEARS BEST ISENTROPIC SUPPORT AND FORCING WILL BE NORTH OF
OUR CWA BY THAT POINT. WILL NEED TO MONITOR SHORT TERM TRENDS.
OTHER IMMEDIATE CONCERN IS POSSIBILITY OF FOG DEVELOPMENT. THERE
HAS BE LIGHT FOG REPORTED OVER PARTS OF SW NEBRASKA...AND WITH
VERY GOOD BL MOISTURE I COULD NT RULE OUT ADDITIONAL FOG
DEVELOPMENT FURTHER SOUTH. THE INHIBITING FACTOR WILL BE
INSULATION FROM CLOUD COVER AND LESS FAVORABLE BL CONDITIONS
BEHIND LIFTING WARM FRONT. HAVE KEPT PATCHY FOG MENTION ACROSS
NORTHERN PART OF CWA THIS MORNING.
AFTER PRECIP ENDS THIS MORNING FORECAST SHOULD REMAIN DRY THROUGH
SUNDAY WITH H5 RIDGE STRENGTHENING...LARGE SCALE SUBSIDENCE
OVER OUR CWA...AND MEAN STORM TRACK SHIFTING NORTH. LEE TROUGH
WILL STRENGTHEN BY THIS WEEKEND WITH HOT AND BREEZY CONDITIONS
EACH AFTERNOON. VERY LITTLE DIFFERENCE REGARDING AIR MASS OVER OUR
CWA...WITH H85 TEMPS IN THE 28-31C RANGE SUPPORTING HIGHS IN THE
UPPER 90S/NEAR 100F. SAW LITTLE REASON TO DEVIATE FROM PREVIOUS
FORECAST WHICH HAD GOOD HANDLE ON MODEL TRENDS. DEPENDING ON
AFTERNOON MIXING WE COULD SEE RH VALUES APPROACH RED FLAG
CRITERIA IN THE WEST SAT/SUN. AT THIS POINT IT DOES NT APPEAR THAT
WE WILL SEE THE WIND/RH CROSSOVER NECESSARY FOR HIGHLIGHTS...BUT
WE WILL NEED TO MONITOR.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 158 PM MDT FRI AUG 23 2013
SATURDAY NIGHT-MONDAY...596 DM H5 RIDGE WILL BE THE DOMINANT FEATURE
IN PLACE ACROSS MUCH OF THE AREA WITH THE RIDGE CENTER EXPECTED TO
GRADUALLY RETROGRADE THROUGH THE PERIOD. PRESENCE OF LARGE AREA OF
SUBSIDENCE AND ONLY WEAK AFTERNOON INSTABILITY PROFILES LEADS ME TO
THINK QUIET WEATHER WILL CONTINUE THROUGH THE PERIOD WITH MAIN AREA
OF CONCERNS BEING TEMPERATURES AND POSSIBLY FIRE WEATHER CONCERNS
WITH THE DRY CONDITIONS.
TEMPERATURES WILL WARM THROUGH THE PERIOD WITH SFC TROUGH EXPECTED
TO KEEP WINDS UP DURING THE OVERNIGHT HOURS WHICH WILL GIVE
TEMPERATURES A RUNNING START EACH DAY AS RADIATIONAL COOLING WILL BE
SOMEWHAT INHIBITED. LOOKS LIKE MID/UPPER 90S TO NEAR 100 CAN BE
EXPECTED BY MONDAY ALTHOUGH RECENT VERIFICATION INDICATES VARIOUS
TEMP FORECASTS HAVE BEEN ON THE WARM SIDE THINGS WHICH DOES LOWER
CONFIDENCE A BIT. GUSTY SOUTHERLY WINDS EXPECTED EACH AFTERNOON AS
SFC TROUGH REMAINS NEARLY STATIONARY. WARM TEMPS WILL HELP PUSH
HUMIDITIES DOWN TO AROUND 20 PERCENT...BUT MIXED LEVEL FORECASTS DO
NOT SUPPORT A STRONG DROP IN DEWPOINTS AT THIS TIME SO POTENTIAL FOR
A CRITICAL FIRE WEATHER DAY APPEAR TO BE LOW.
IN THE EXTENDED (MON NIGHT-FRI)...GENERAL CONSENSUS OF MEDIUM RANGE
MODELS SUPPORTS STRONG H5 RIDGE RETROGRADING SLIGHTLY WITH RIDGE
CENTER NEARING THE CWA AND PERSISTING THERE THROUGH THE WEEK.
CONTINUED WARM AND DRY CONDITIONS CAN BE EXPECTED AND WILL HAVE TO
WATCH WIND SPEEDS CLOSELY AS HUMIDITIES WILL NEAR CRITICAL FIRE
WEATHER VALUES EACH AFTERNOON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI AUG 23 2013
VFR CONDITIONS EXPECTED AT KGLD AND KMCK. A MESOSCALE CONVECTIVE
VORTICE...LEFTOVER FROM SHOWERS AND THUNDERSTORMS ACROSS THE
COLORADO FRONT RANGE YESTERDAY...IS SPINNING OVER THE AREA THIS
MORNING. THIS SYSTEM IS EXPECTED TO CONTINUE TO SLOWLY MOVE
EAST/NORTHEAST THROUGH THE REST OF THE DAY EXITING THE AREA EARLY
TONIGHT. THE COMBINATION OF DIURNAL HEATING AND THIS DISTURBANCE
SHOULD PRODUCE SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EARLY EVENING. MOST LIKELY LOCATION TO POTENTIALLY BE IMPACTED
WOULD BE KMCK. HOWEVER...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN
TAF AT PRESENT TIME. OTHERWISE...BOTH TERMINALS CAN EXPECT AN
INCREASE IN WINDS THIS AFTERNOON AND EVENING WHERE GUSTS AROUND
20KTS POSSIBLE. SOUTHERLY WINDS WILL INCREASE IN SPEED DURING THE
DAY SATURDAY WITH GUSTS OF 25-30KTS POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...JRM
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
204 PM CDT Fri Aug 23 2013
...Updated Short term discussion...
.SYNOPSIS...
ISSUED AT 1208 PM CDT FRI AUG 23 2013
At 12z Friday a 500mb trough was located over northern California
and the pacific northwest. A 500mb high was located across western
Oklahoma. An upper level ridge axis extended from this upper high
northward into south central Canada. 700mb temperatures at 12z
this morning across the central high plains ranged from 11c at
Dodge City and North Platte to +16c at Denver. A 850mb baroclinic
zone extended from southwest Nebraska to northeast Oklahoma.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 202 PM CDT FRI AUG 23 2013
Water Vapor loop indicating an upper level disturbance was moving
north across east central Colorado earlier this morning. The 12z
RAP, NAM,and GFS 400-450mb potential vorticity field picked up on
this feature fairly well and currently moves this feature across
northern Kansas early this evening. NAM and to a lesser degree RAP
and HRRR even hints at some precipitation this evening near and
north of I70 as this wave passes. Given the late day instability
expected ahead of this wave the chance for an isolated
thunderstorm or two can not be ruled out...especially near the
Nebraska border. At this time am leaning towards leaving mention
of thunderstorms out of the forecast near the interstate 70
corridor given the better instability and forcing is forecast to
be further north. Will however insert a mention of isolated
thunderstorms if convection appears to be developing further south
than anticipated.
Skies are expected to clear from west to east as this upper wave
passes north central Kansas after midnight. Given surface
dewpoints in the 60s and surface winds at 10kts will stay close to
the previous forecast with overnight ranging from the mid 60s in
far western Kansas to around 70 in north central and south central
Kansas.
On Saturday an upper high will slowly move east across southwest
Kansas and 800mb temperatures at 00z Sunday are forecast range
from 24c to 28c. This suggests highs Saturday afternoon mainly in
the mid 90s given full sun.
.LONG TERM...(Saturday through Thursday)
ISSUED AT 226 AM CDT FRI AUG 23 2013
For the extended period from Saturday night through next Friday,
very little has change has shown up in the medium and long range
models. A upper level high pressure area will essentially be
anchored over the Sunflower State through the foreseeable future.
This upper high will bring a lot of sunshine to western Kansas,
resulting in afternoon highs in the mid to upper 90s. Will the 100F
degree mark be reached? Possibly by Wednesday or beyond. The
prolonged pattern of upper high pressure and a long southwest fetch
of warming winds at the surface may be just enough for a couple of
spots in western Kansas to peak near or over 100F. For now, have
accepted what the CR_Extended tool produced, with 97F-98F max temps
ranges. The only clouds expected through Friday are mid and high
level in nature. These clouds will not alter or slow down the
surface heating. Furthermore, a lee side trough will form each
afternoon across eastern Colorado, and will edge eastward nearly
every day into western Kansas. Unfortunately, there will be little
or no substantial moisture to work with, and thus there are no
precipitation chances included in the extended period.
Minimum temperatures will basically be in the lower to mid 70s, but
creep slowly upward with time. By Friday, expect lows in the mid
70s in our eastern zones of Barber, Comanche and Pratt counties, and
around the 70F degree mark along the Colorado border. In general,
winds will be from the south to southwest, dipping to 10 to 15 mph
overnight, and then increasing by late mornings into the 15 to 25
mph and gusty range.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1208 PM CDT FRI AUG 23 2013
VFR conditions can be expected through tonight at all TAF sites. As
surface troughing persist on the lee side of the Rockies, winds will
remain southerly this afternoon and evening from 10 to 15 kt. A few
gusts around 25 kt could be possible this afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 94 72 94 / 0 0 0 0
GCK 68 94 71 95 / 0 0 0 0
EHA 64 94 70 93 / 0 0 0 0
LBL 67 95 72 95 / 0 0 0 0
HYS 70 94 72 95 / 0 0 0 0
P28 71 94 73 94 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Burke
AVIATION...Scott
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1220 PM CDT Fri Aug 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 335 AM CDT FRI AUG 23 2013
A broad upper level ridge of high pressure will be centered over the
state of Kansas for the next 24 hours.
early this morning, elevated showers were developing due to weak
isentropic lift north of an old outflow boundary across west central
KS. At this time I think the showers should remain just west of the
cwa...though some isolated showers may develop near sunrise across
the southwest and northern counties of the CWA, but should dissipate
by mid morning. May place a 10 to 14 pop across the southwest and
northern counties in case any isolated showers develop.
Widespread convection along the foothills of CO will cause periods
of high clouds to move across the CWA Today. The 06Z NAM is the only
numerical model that breaks out deep moist convection across north
central KS late this afternoon and into the early evening hours. The
NAM may be trying to bring the MCV from the CO foothill convective
complex too far south across the center of the H5 ridge axis. The
GFS, arw, nmm and RAP show the the mcv rotating farther northeast
across western and central NE and show no qpf developing across
north central KS this afternoon. Just in case the NAM solution may
be accurate I inserted 10 to 14 pops for late this afternoon and
early evening across the northwest counties of the CWA.
High temperatures Today may be dependent on the amount of high
clouds. if the high clouds thin out this afternoon then highs will
reach into the lower to mid 90s. If we keep a thicker veil of high
clouds through the afternoon hours, then highs may only reach the
upper 80s to around 90.
Tonight, if any showers or isolated thunderstorms develop across
north central KS they should dissipate after sunset. skies should
become mostly clear through the night. overnight lows will drop into
the upper 60s to lower 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 335 AM CDT FRI AUG 23 2013
Medium range models are very similar in building upper ridge
eastward through the weekend with axis over MO before retrogressing
slightly and amplifying across KS through most of next week. This
will allow for only weak inhibition by peak heating over the
weekend...but a strengthening cap into next week. However with the
exception of diurnal heating...no significant forcing evident to
warrant any pops at this point...and even less confidence into next
week. Therefore will keep the fcst through the extended dry. The
llvl thermal fields only warm slightly from the weekend into the
middle of next week...so the current fcst of only minor high temp
increases thru the middle 90s into next week looks good for now.
There is some concern that soil conditions steadily drying out and
some hint of more veering llvl windfields by the middle of next week
could lead to higher temps in the western cwa. A slight increase in
dewpoints into next week with the slightly warmer temps should inch
heat indices to around the century mark for most areas through next
week.
&&
.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1216 PM CDT FRI AUG 23 2013
Will keep vfr conditions through the period and monitor for some
outside chances for convection toward the end of the taf cycle,
but at this time seems to stay north of the terminals. 67
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...63
AVIATION...67
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1100 AM MDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 559 AM MDT FRI AUG 23 2013
JUST FINISHED QUICK UPDATE TO POP/WX TO REFLECT CURRENT COVERAGE
OF SHOWERS/THUNDERSTORMS IN EASTER CWA. ALSO LINGERING SLIGHT
CHANCE POPS IN NORTHERN CWA THROUGH DAY TO ACCOUNT FOR POSSIBLE
SHOWERS/THUNDERSTORMS REDEVELOPING AS MESO-LOW FROM OVERNIGHT
CONVECTION OVER NE COLORADO SLOWLY MOVES OVER CWA. THERE APPEARS
TO BE SOME REFLECTION AT H7-H5 FROM RAP WITH THIS FEATURE. LATEST
HRRR WOULD ACTUALLY SUPPORT BETTER COVERAGE AFTER
SUNRISE...HOWEVER WITH VERY LITTLE RETURNS YET THIS MORNING WILL
STAY CONSERVATIVE WITH THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 251 AM MDT FRI AUG 23 2013
LATEST WV IMAGERY AND H5 ANALYSIS SHOWS LARGE SCALE RIDGE OVER
THE CENTRAL US...CENTERED OVER THE SOUTHERN PLAINS. A STALLED
FRONT EXTENDS SOUTH ALONG THE FRONT RANGE IN COLORADO AND BACK TO
THE EAST AS A WARM FRONT OVER THE SOUTHERN HALF OF OUR CWA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY
THIS MORNING ACROSS OUR CWA AS A WARM FRONT HAS LIFTED NORTH WITH
GOOD MOISTURE AND MARGINAL INSTABILITY IN PLACE...AND SUPPORT FROM
LLJ/MID LEVEL THETA-E CONVERGENCE. SHORT RANGE GUIDANCE HAS DECENT
HANDLE ON SHOWERS/THUNDERSTORMS IN EASTERN COLORADO...HOWEVER IS
NOT DOING A GOOD JOB WITH ACTIVITY ALONG FRONT ACROSS REST OF CWA.
WHILE CHANCE OF MEASURABLE IS NOT AS GREAT...COVERAGE ON RADAR HAS
INCREASED QUITE A BIT OVER THE LAST FEW HOURS...SO I WENT AHEAD
AND INCREASE POPS TO CHANCE CATEGORY. IVE TRENDED THIS ACTIVITY
NORTHWARD THROUGH SUNRISE BASED ON TIMING OF FRONT. I COULD NT
RULE OUT ACTIVITY POSSIBLY LINGERING THROUGH MID MORNING...HOWEVER
IT APPEARS BEST ISENTROPIC SUPPORT AND FORCING WILL BE NORTH OF
OUR CWA BY THAT POINT. WILL NEED TO MONITOR SHORT TERM TRENDS.
OTHER IMMEDIATE CONCERN IS POSSIBILITY OF FOG DEVELOPMENT. THERE
HAS BE LIGHT FOG REPORTED OVER PARTS OF SW NEBRASKA...AND WITH
VERY GOOD BL MOISTURE I COULD NT RULE OUT ADDITIONAL FOG
DEVELOPMENT FURTHER SOUTH. THE INHIBITING FACTOR WILL BE
INSULATION FROM CLOUD COVER AND LESS FAVORABLE BL CONDITIONS
BEHIND LIFTING WARM FRONT. HAVE KEPT PATCHY FOG MENTION ACROSS
NORTHERN PART OF CWA THIS MORNING.
AFTER PRECIP ENDS THIS MORNING FORECAST SHOULD REMAIN DRY THROUGH
SUNDAY WITH H5 RIDGE STRENGTHENING...LARGE SCALE SUBSIDENCE
OVER OUR CWA...AND MEAN STORM TRACK SHIFTING NORTH. LEE TROUGH
WILL STRENGTHEN BY THIS WEEKEND WITH HOT AND BREEZY CONDITIONS
EACH AFTERNOON. VERY LITTLE DIFFERENCE REGARDING AIR MASS OVER OUR
CWA...WITH H85 TEMPS IN THE 28-31C RANGE SUPPORTING HIGHS IN THE
UPPER 90S/NEAR 100F. SAW LITTLE REASON TO DEVIATE FROM PREVIOUS
FORECAST WHICH HAD GOOD HANDLE ON MODEL TRENDS. DEPENDING ON
AFTERNOON MIXING WE COULD SEE RH VALUES APPROACH RED FLAG
CRITERIA IN THE WEST SAT/SUN. AT THIS POINT IT DOES NT APPEAR THAT
WE WILL SEE THE WIND/RH CROSSOVER NECESSARY FOR HIGHLIGHTS...BUT
WE WILL NEED TO MONITOR.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 251 AM MDT FRI AUG 23 2013
WHILE THE PAST FEW EXTENDED RANGE FORECASTS HAVE SOUNDED LIKE A
BROKEN RECORD - HOT AND DRY - IT APPEARS AN END IS IN SIGHT. EARLY
NEXT WEEK AN UPPER LEVEL RIDGE WILL BE CENTERED OVER KANSAS...WITH A
A NORTH-SOUTH ORIENTED SURFACE TROUGH DEVELOP ALONG EASTERN
COLORADO. THE ECMWF HAD PREVIOUSLY BEEN A BIT MORE CONSERVATIVE WITH
TEMPS BUT NOW HAS COME AROUND TO BETTER MATCH THE GFS AND GEM WITH
TEMPS IN THE LOW 30S C...TRANSLATING TO MID TO UPPER 90S IN THE
FIRST HALF OF THE WEEK. TRIPLE-DIGIT TEMPS LOOK ALMOST LIKELY ON
MONDAY AND TUESDAY FOR THE NORMAL HOT SPOTS...PLACES LIKE
TRIBUNE...HILL CITY...AND MCCOOK...APPROACHING /BUT PROBABLY NOT
EXCEEDING/ RECORDS IN SOME SPOTS. LATER IN THE WEEK THE RIDGE WILL
SLOWLY NUDGE FARTHER EAST BRINGING RELIEF TO THE HEAT...SOMETHING
THE OPERATIONAL GFS IS A BIT SLOW TO REALIZE BUT THE GEFS MEAN AND
ECMWF HAVE BEEN CONSISTENT WITH THE PAST FEW RUNS. PRECIP CHANCES
ARE NEAR NIL WITH THE RIDGE OVER US...BUT AS IT MOVES EAST WE COULD
SEE CHANCES INCREASE TOWARDS THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI AUG 23 2013
VFR CONDITIONS EXPECTED AT KGLD AND KMCK. A MESOSCALE CONVECTIVE
VORTICE...LEFTOVER FROM SHOWERS AND THUNDERSTORMS ACROSS THE
COLORADO FRONT RANGE YESTERDAY...IS SPINNING OVER THE AREA THIS
MORNING. THIS SYSTEM IS EXPECTED TO CONTINUE TO SLOWLY MOVE
EAST/NORTHEAST THROUGH THE REST OF THE DAY EXITING THE AREA EARLY
TONIGHT. THE COMBINATION OF DIURNAL HEATING AND THIS DISTURBANCE
SHOULD PRODUCE SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EARLY EVENING. MOST LIKELY LOCATION TO POTENTIALLY BE IMPACTED
WOULD BE KMCK. HOWEVER...CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN
TAF AT PRESENT TIME. OTHERWISE...BOTH TERMINALS CAN EXPECT AN
INCREASE IN WINDS THIS AFTERNOON AND EVENING WHERE GUSTS AROUND
20KTS POSSIBLE. SOUTHERLY WINDS WILL INCREASE IN SPEED DURING THE
DAY SATURDAY WITH GUSTS OF 25-30KTS POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...JJM
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
605 AM MDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 559 AM MDT FRI AUG 23 2013
JUST FINISHED QUICK UPDATE TO POP/WX TO REFLECT CURRENT COVERAGE
OF SHOWERS/THUNDERSTORMS IN EASTER CWA. ALSO LINGERING SLIGHT
CHANCE POPS IN NORTHERN CWA THROUGH DAY TO ACCOUNT FOR POSSIBLE
SHOWERS/THUNDERSTORMS REDEVELOPING AS MESO-LOW FROM OVERNIGHT
CONVECTION OVER NE COLORADO SLOWLY MOVES OVER CWA. THERE APPEARS
TO BE SOME REFLECTION AT H7-H5 FROM RAP WITH THIS FEATURE. LATEST
HRRR WOULD ACTUALLY SUPPORT BETTER COVERAGE AFTER
SUNRISE...HOWEVER WITH VERY LITTLE RETURNS YET THIS MORNING WILL
STAY CONSERVATIVE WITH THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 251 AM MDT FRI AUG 23 2013
LATEST WV IMAGERY AND H5 ANALYSIS SHOWS LARGE SCALE RIDGE OVER
THE CENTRAL US...CENTERED OVER THE SOUTHERN PLAINS. A STALLED
FRONT EXTENDS SOUTH ALONG THE FRONT RANGE IN COLORADO AND BACK TO
THE EAST AS A WARM FRONT OVER THE SOUTHERN HALF OF OUR CWA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY
THIS MORNING ACROSS OUR CWA AS A WARM FRONT HAS LIFTED NORTH WITH
GOOD MOISTURE AND MARGINAL INSTABILITY IN PLACE...AND SUPPORT FROM
LLJ/MID LEVEL THETA-E CONVERGENCE. SHORT RANGE GUIDANCE HAS DECENT
HANDLE ON SHOWERS/THUNDERSTORMS IN EASTERN COLORADO...HOWEVER IS
NOT DOING A GOOD JOB WITH ACTIVITY ALONG FRONT ACROSS REST OF CWA.
WHILE CHANCE OF MEASURABLE IS NOT AS GREAT...COVERAGE ON RADAR HAS
INCREASED QUITE A BIT OVER THE LAST FEW HOURS...SO I WENT AHEAD
AND INCREASE POPS TO CHANCE CATEGORY. IVE TRENDED THIS ACTIVITY
NORTHWARD THROUGH SUNRISE BASED ON TIMING OF FRONT. I COULD NT
RULE OUT ACTIVITY POSSIBLY LINGERING THROUGH MID MORNING...HOWEVER
IT APPEARS BEST ISENTROPIC SUPPORT AND FORCING WILL BE NORTH OF
OUR CWA BY THAT POINT. WILL NEED TO MONITOR SHORT TERM TRENDS.
OTHER IMMEDIATE CONCERN IS POSSIBILITY OF FOG DEVELOPMENT. THERE
HAS BE LIGHT FOG REPORTED OVER PARTS OF SW NEBRASKA...AND WITH
VERY GOOD BL MOISTURE I COULD NT RULE OUT ADDITIONAL FOG
DEVELOPMENT FURTHER SOUTH. THE INHIBITING FACTOR WILL BE
INSULATION FROM CLOUD COVER AND LESS FAVORABLE BL CONDITIONS
BEHIND LIFTING WARM FRONT. HAVE KEPT PATCHY FOG MENTION ACROSS
NORTHERN PART OF CWA THIS MORNING.
AFTER PRECIP ENDS THIS MORNING FORECAST SHOULD REMAIN DRY THROUGH
SUNDAY WITH H5 RIDGE STRENGTHENING...LARGE SCALE SUBSIDENCE
OVER OUR CWA...AND MEAN STORM TRACK SHIFTING NORTH. LEE TROUGH
WILL STRENGTHEN BY THIS WEEKEND WITH HOT AND BREEZY CONDITIONS
EACH AFTERNOON. VERY LITTLE DIFFERENCE REGARDING AIR MASS OVER OUR
CWA...WITH H85 TEMPS IN THE 28-31C RANGE SUPPORTING HIGHS IN THE
UPPER 90S/NEAR 100F. SAW LITTLE REASON TO DEVIATE FROM PREVIOUS
FORECAST WHICH HAD GOOD HANDLE ON MODEL TRENDS. DEPENDING ON
AFTERNOON MIXING WE COULD SEE RH VALUES APPROACH RED FLAG
CRITERIA IN THE WEST SAT/SUN. AT THIS POINT IT DOES NT APPEAR THAT
WE WILL SEE THE WIND/RH CROSSOVER NECESSARY FOR HIGHLIGHTS...BUT
WE WILL NEED TO MONITOR.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 251 AM MDT FRI AUG 23 2013
WHILE THE PAST FEW EXTENDED RANGE FORECASTS HAVE SOUNDED LIKE A
BROKEN RECORD - HOT AND DRY - IT APPEARS AN END IS IN SIGHT. EARLY
NEXT WEEK AN UPPER LEVEL RIDGE WILL BE CENTERED OVER KANSAS...WITH A
A NORTH-SOUTH ORIENTED SURFACE TROUGH DEVELOP ALONG EASTERN
COLORADO. THE ECMWF HAD PREVIOUSLY BEEN A BIT MORE CONSERVATIVE WITH
TEMPS BUT NOW HAS COME AROUND TO BETTER MATCH THE GFS AND GEM WITH
TEMPS IN THE LOW 30S C...TRANSLATING TO MID TO UPPER 90S IN THE
FIRST HALF OF THE WEEK. TRIPLE-DIGIT TEMPS LOOK ALMOST LIKELY ON
MONDAY AND TUESDAY FOR THE NORMAL HOT SPOTS...PLACES LIKE
TRIBUNE...HILL CITY...AND MCCOOK...APPROACHING /BUT PROBABLY NOT
EXCEEDING/ RECORDS IN SOME SPOTS. LATER IN THE WEEK THE RIDGE WILL
SLOWLY NUDGE FARTHER EAST BRINGING RELIEF TO THE HEAT...SOMETHING
THE OPERATIONAL GFS IS A BIT SLOW TO REALIZE BUT THE GEFS MEAN AND
ECMWF HAVE BEEN CONSISTENT WITH THE PAST FEW RUNS. PRECIP CHANCES
ARE NEAR NIL WITH THE RIDGE OVER US...BUT AS IT MOVES EAST WE COULD
SEE CHANCES INCREASE TOWARDS THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 529 AM MDT FRI AUG 23 2013
SHOWERS/THUNDERSTORMS WILL LINGER WITHIN VICINITY OF KMCK
TERMINAL THROUGH MID MORNING BEFORE ACTIVITY DISSIPATES OR SHIFTS
NORTH/EAST. CANT COMPLETELY RULE OUT ADDITIONAL ACTIVITY
REDEVELOPING LATER TODAY WITH SMALL SCALE LOW IN EASTERN
COLORADO...HOWEVER WILL HOLD THIS OUT OF TAFS FOR NOW. OTHER
AVIATION CONCERN THIS MORNING WITH BE PATCHY FOG. MVFR CIGS HAVE
BEEN REPORTED AT TIMES AT KMCK...THOUGH WITH PRECIP IN VICINITY
AND WINDS SHIFTING TO THE SOUTH I DONT THINK THIS WILL PREVAIL.
KGLD SHOULD REMAIN WITHIN VFR...THOUGH WITH BETTER CHANCE TO SEE
CLEARING SKIES AROUND SUNRISE I DONT WANT TO COMPLETELY RULE OUT
MVFR VIS DEVELOPING FOR A SHORT PERIOD THIS MORNING. WILL LEAVE
TEMPO IN PLACE AT KMCK FOR NOW...AND KEEP KGLD AT 6SM. BEYOND THIS
MORNING VFR CONDITIONS SHOULD PREVAIL. LIGHTS WINDS WILL BEGIN TO
INCREASE OUT OF THE THE SOUTH THIS AFTERNOON WITH LEE TROUGH
DEVELOPMENT...WITH SUSTAINED WINDS GENERALLY AROUND 13-15KT...AND
OCCASIONAL GUSTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
623 AM CDT Fri Aug 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 335 AM CDT FRI AUG 23 2013
A broad upper level ridge of high pressure will be centered over the
state of Kansas for the next 24 hours.
early this morning, elevated showers were developing due to weak
isentropic lift north of an old outflow boundary across west central
KS. At this time I think the showers should remain just west of the
cwa...though some isolated showers may develop near sunrise across
the southwest and northern counties of the CWA, but should dissipate
by mid morning. May place a 10 to 14 pop across the southwest and
northern counties in case any isolated showers develop.
Widespread convection along the foothills of CO will cause periods
of high clouds to move across the CWA Today. The 06Z NAM is the only
numerical model that breaks out deep moist convection across north
central KS late this afternoon and into the early evening hours. The
NAM may be trying to bring the MCV from the CO foothill convective
complex too far south across the center of the H5 ridge axis. The
GFS, arw, nmm and RAP show the the mcv rotating farther northeast
across western and central NE and show no qpf developing across
north central KS this afternoon. Just in case the NAM solution may
be accurate I inserted 10 to 14 pops for late this afternoon and
early evening across the northwest counties of the CWA.
High temperatures Today may be dependent on the amount of high
clouds. if the high clouds thin out this afternoon then highs will
reach into the lower to mid 90s. If we keep a thicker veil of high
clouds through the afternoon hours, then highs may only reach the
upper 80s to around 90.
Tonight, if any showers or isolated thunderstorms develop across
north central KS they should dissipate after sunset. skies should
become mostly clear through the night. overnight lows will drop into
the upper 60s to lower 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 335 AM CDT FRI AUG 23 2013
Medium range models are very similar in building upper ridge
eastward through the weekend with axis over MO before retrogressing
slightly and amplifying across KS through most of next week. This
will allow for only weak inhibition by peak heating over the
weekend...but a strengthening cap into next week. However with the
exception of diurnal heating...no significant forcing evident to
warrant any pops at this point...and even less confidence into next
week. Therefore will keep the fcst through the extended dry. The
llvl thermal fields only warm slightly from the weekend into the
middle of next week...so the current fcst of only minor high temp
increases thru the middle 90s into next week looks good for now.
There is some concern that soil conditions steadily drying out and
some hint of more veering llvl windfields by the middle of next week
could lead to higher temps in the western cwa. A slight increase in
dewpoints into next week with the slightly warmer temps should inch
heat indices to around the century mark for most areas through next
week.
&&
.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 619 AM CDT FRI AUG 23 2013
Expect VFR conditions for the next 24 hours at the TAF sites. The mid
level clouds should prevent widespread ground fog at both KMHK and
KTOP this morning. FEW to SCT CU will develop this afternoon and
should dissipate after sunset. FEW-SCT mid and high clouds
Tonight.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...63
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS TOPEKA KS
340 AM CDT Fri Aug 23 2013
.SHORT TERM...(Today and Tonight)
Issued at 335 AM CDT FRI AUG 23 2013
A broad upper level ridge of high pressure will be centered over the
state of Kansas for the next 24 hours.
early this morning, elevated showers were developing due to weak
isentropic lift north of an old outflow boundary across west central
KS. At this time I think the showers should remain just west of the
cwa...though some isolated showers may develop near sunrise across
the southwest and northern counties of the CWA, but should dissipate
by mid morning. May place a 10 to 14 pop across the southwest and
northern counties in case any isolated showers develop.
Widespread convection along the foothills of CO will cause periods
of high clouds to move across the CWA Today. The 06Z NAM is the only
numerical model that breaks out deep moist convection across north
central KS late this afternoon and into the early evening hours. The
NAM may be trying to bring the MCV from the CO foothill convective
complex too far south across the center of the H5 ridge axis. The
GFS, arw, nmm and RAP show the the mcv rotating farther northeast
across western and central NE and show no qpf developing across
north central KS this afternoon. Just in case the NAM solution may
be accurate I inserted 10 to 14 pops for late this afternoon and
early evening across the northwest counties of the CWA.
High temperatures Today may be dependent on the amount of high
clouds. if the high clouds thin out this afternoon then highs will
reach into the lower to mid 90s. If we keep a thicker veil of high
clouds through the afternoon hours, then highs may only reach the
upper 80s to around 90.
Tonight, if any showers or isolated thunderstorms develop across
north central KS they should dissipate after sunset. skies should
become mostly clear through the night. overnight lows will drop into
the upper 60s to lower 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 335 AM CDT FRI AUG 23 2013
Medium range models are very similar in building upper ridge
eastward through the weekend with axis over MO before retrogressing
slightly and amplifying across KS through most of next week. This
will allow for only weak inhibition by peak heating over the
weekend...but a strengthening cap into next week. However with the
exception of diurnal heating...no significant forcing evident to
warrant any pops at this point...and even less confidence into next
week. Therefore will keep the fcst through the extended dry. The
llvl thermal fields only warm slightly from the weekend into the
middle of next week...so the current fcst of only minor high temp
increases thru the middle 90s into next week looks good for now.
There is some concern that soil conditions steadily drying out and
some hint of more veering llvl windfields by the middle of next week
could lead to higher temps in the western cwa. A slight increase in
dewpoints into next week with the slightly warmer temps should inch
heat indices to around the century mark for most areas through next
week.
&&
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1148 PM CDT THU AUG 22 2013
Light to calm winds and mostly clear skies may lead to some MVFR
VSBYS at TOP and MHK from 10 to 13Z and have added a tempo group
for now. Outside of any fog VFR conditions are expected. South
southeast winds will increase to around 10 kts by 16Z, then
decrease after 01Z Saturday.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...63
AVIATION...53
AREA FORECAST DISCUSSION
NWS JACKSON KY
147 AM EDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 1055 PM EDT THU AUG 22 2013
WENT AHEAD AND LOWERED POPS A BIT MORE THROUGH THE OVERNIGHT WITH
CONVECTION DYING OFF. THE HRRR AND RAP13 MODELS STILL REGENERATE SOME
ACTIVITY TOWARDS DAWN...AND WILL CONTINUE TO ROLL WITH AN UPTICK IN POPS
FOR NOW.
UPDATE ISSUED AT 836 PM EDT THU AUG 22 2013
CONVECTION SEEMS TO BE ON THE DECLINE BESIDES A MORE ORGANIZED LINE
OF SHOWERS AND THUNDERSTORMS AFFECTING WEST VIRGINIA...AS WELL AS
SOME SLIGHTLY BETTER CLUSTERED CONVECTION GENERATED FROM A PASSING
OUTFLOW BOUNDARY OUT IN NORTH CENTRAL KENTUCKY. AS SUCH...HAVE LOWERED
POPS FOR THE REST OF THIS EVENING. THE LAST FEW HRRR RUNS HAVE ALSO
SHOWN A GENERAL DECLINE THROUGH THE EVENING. ONCE THE REMAINS OF THE
FRONTAL BOUNDARY AND A PASSING SHORT WAVE TROUGH MOVE THROUGH CLOSER
TO DAWN...SOME SLIGHTLY BETTER COVERAGE WILL BE POSSIBLE...MAINLY IN
THE NORTHEAST. STILL...GIVEN THE CURRENT OVERALL DOWNWARD
TREND...FELT IT WARRANTED TO TRIM BACK THE POPS A BIT INTO THE DAY ON
FRIDAY AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 337 PM EDT THU AUG 22 2013
ISOLATED TO SCATTERED CONVECTION ACROSS THE AREA HAS REMAINED
UNORGANIZED AND TAME SO FAR TODAY...WITH LITTLE UPPER LEVEL SUPPORT
AVAILABLE. A SHORT WAVE ON WATER VAPOR IMAGERY OVER THE UPPER MS
VALLEY IS MOVING ESE...WHILE AN OLD OUTFLOW BOUNDARY AT THE SURFACE
IS FOCUSING CONVECTIVE DEVELOPMENT ACROSS CENTRAL OH AND INDIANA.
AS THE SHORT WAVE MOVES INTO THE OH VALLEY TONIGHT...THERE WILL BE
BETTER UPPER LEVEL SUPPORT FOR PRECIPITATION ACROSS THE FORECAST
AREA. THE EXACT EVOLUTION OF CONVECTION DEVELOPING ACROSS OH AND
INDIANA IS UNCERTAIN...AND THE 17Z HRRR HAS MOST PRECIPITATION DYING
OUT BY 02Z. HOWEVER IT DOES SHOW REDEVELOPMENT AROUND 05Z MOST
LIKELY IN ASSOCIATION WITH AN UPPER LEVEL SPEED MAX ASSOCIATED WITH
THE UPPER TROF. THE NAM IS MOST SUPPORTIVE OF PRECIPITATION
OVERNIGHT...BUT THE GFS...ECMWF AND GEM ALL POINT TOWARDS A CHANCE
OF SHOWERS AND THUNDERSTORMS. IT DOES APPEAR THE BEST SUPPORT WILL BE
OVER THE NORTHERN AND EASTERN PORTION OF THE FORECAST AREA AND HAVE
ELECTED TO GO WITH LIKELY PROBABILITY OF RAIN CHANCES IN THESE AREAS
WITH A CHANCE IN THE SOUTHWEST. WEAK COLD FRONT WILL NOT CLEAR THE
AREA UNTIL FRIDAY EVENING...SO WILL CONTINUE WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS FRIDAY...BUT DECREASE CHANCES FROM THE NORTH DURING
THE DAY.
WITH PRECIPITABLE WATER AROUND 1.9 INCHES OR NEAR THE 90TH
PERCENTILE...WILL CONTINUE TO MENTION HEAVY RAIN AND FLASH FLOOD
POSSIBILITY IN THE HAZARDOUS WEATHER OUTLOOK FOR TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 PM EDT THU AUG 22 2013
OT A LOT OF CHANGE FROM PREVIOUS FORECAST. MODELS ARE STILL IN
RELATIVELY GOOD AGREEMENT THAT THE UPPER AIR PATTERN WILL CONSIST OF
A LARGE 500MB RIDGE ACROSS THE SOUTH CENTRAL CONUS...EXPECTED TO
REMAIN IN PLACE THROUGH THE DURATION OF THE FORECAST PERIOD. WITH
UPPER LEVEL TROUGHING OFF BOTH THE NW AND NE COAST...EASTERN KY WILL
FIND ITSELF WITHIN THE RIDGING PATTERN...BUT ON THE WINDWARD SIDE OF
THE NE TROUGHING PATTERN. ANY SHORTWAVE THAT TRAVELS ALONG THE
TROUGH AXIS WILL MAKE ITS WAY NEAR EASTERN KY DESPITE THE STRONG
RIDGING IN PLACE. HOWEVER...WITH SOMEWHAT LESS AGREEMENT ON THE
SMALLER SCALE...ANY SHORTWAVES AND RESULTING RAIN CHANCES WILL BE
BEST LEFT TO A MODEL CONSENSUS.
WITH A GOOD VEERING WIND PROFILE...AND TEMPERATURES EXPECTED TO BE
WARMER AND MORE HUMID THAN HAVE BEEN OVER THE PAST FEW WEEKS...ALL
MODELS ARE POINTING AT THE POTENTIAL FOR AFTERNOON INSTABILITY AND
CONVECTION ACROSS THE EASTERN PORTION OF THE STATE THROUGH THE
ENTIRE FORECAST PERIOD. THE ONLY CAVEAT TO THIS IS THE FACT THAT
GFS40 SOUNDINGS /BOTH CURRENT AND PREVIOUS/ ARE SHOWING AN ABUNDANT
AMOUNT OF DRY AIR AT ALL LEVELS...WITH ONLY THE POTENTIAL FOR A SCT
THIN LAYER OF DIURNAL CLOUDS. AND THOUGH THERE IS A GOOD VEERING
PATTERN MENTIONED ABOVE...MOST OF THIS TAKES PLACE IN THE MID LEVELS
RATHER THAN THE LOWER LEVELS...WITH A LOW AMOUNT OF CAPE AND A VERY
LIMITED AMOUNT OF TIME IN THE AFTERNOON WHERE THERE IS NOT A CAPPING
INVERSION. ALL THINGS CONSIDERED...DID PUT IN SOME SLIGHT CHANCE
POPS IN THE AFTERNOON TO GO ALONG WITH MODEL CONSENSUS...BUT EXPECT
THUNDERSTORM DEVELOPMENT TO BE EVEN MORE ISOLATED IN COMPARISON TO
SHOWER POTENTIAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 146 AM EDT FRI AUG 23 2013
FOG WILL CONTINUE TO DEVELOP TONIGHT...THICKENING IN THE DEEPER
VALLEYS AND SPREADING OUT FROM THERE. NOT CONFIDENT IN EVENTUAL
OUTCOMES AT TAF SITES...BUT AT LEAST MVFR CAN BE EXPECTED AT TIMES...
AND POSSIBLY IFR. ISOLATED SHOWERS COULD ALSO REDEVELOP TOWARD
DAWN...ESPECIALLY IN THE NE PART OF THE AREA. FOG WILL THEN DISSIPATE
WELL AFTER SUNRISE...POSSIBLY BRIEFLY LIFTING INTO AN IFR OR LOW MVFR
CLOUD DECK BEFORE RISING FURTHER AND SCATTERING LATER IN THE MORNING.
WITH DAYTIME HEATING...SCATTERED THUNDERSTORMS MAY BE A THREAT DURING
THE MID-LATE AFTERNOON HOURS. OUTSIDE OF PRECIP IN THE AFTERNOON AND
EVENING...VFR IS EXPECTED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SBH
LONG TERM...JMW
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
741 PM EDT SAT AUG 24 2013
.SYNOPSIS...
HIGH PRESSURE AND PLEASANT WEATHER WILL CONTINUE THROUGH THE
WEEKEND. AN UPPER-LEVEL DISTURBANCE WILL APPROACH EARLY NEXT WEEK
AND WILL GIVE US THE CHANCE OF SHOWERS AND STORMS. TEMPERATURES
WILL CLIMB ABOVE NORMAL BY THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
600 PM UPDATE...
DEW POINTS CONTINUE TO SLOWLY DROP. NUDGED MIN TEMPS DOWN ACROSS
NORTH WITH LOWER TD/S. BROUGHT IN A LITTLE MORE CLOUDS (CIRRUS)
TOWARD MORNING. HRRR SUGGESTING SOME BLOW OFF DEBRIS FROM SYSTEM
JUST NORTH OF GREAT LAKES. KEPT A FEW MORE CLOUDS RIDGES
APPALACHIAN PLATEAU COUNTIES. WITH EAST TO NORTHEAST FLOW COULD
CONTINUE A FEW UP-SLOPE CLOUDS.
PREVIOUS DISCUSSION FOLLOWS...
DRY ADIABATIC CONDITIONS FROM CCL TO SFC HAVE DEVELOPED A SCT CU
FIELD ACROSS THE HIGHER TERRAIN AND POINTS S OF I-70. THIS FIELD
WILL CONTINUE TO GROW THIS AFTN AS TEMPS CLIMB INTO THE M-U 70S.
DAYTIME DRIVEN CU WILL WANE WITH SUNSET...LEAVING A CLR- MCLR SKY.
CROSSOVER TEMPS OF M-U 50S WOULD NOT YIELD FOG FORMATION OVERNIGHT
EVEN IN THE DEEPER HOLLOWS OF THE NRN WV MTNS.
H5 HEIGHTS BUILD SUN AS ANTICYCLONE OVER THE MIDWEST SHIFTS A
LITTLE E. BUFR SOUNDINGS ILLUSTRATE AN INC IN MID AND HIGH CLOUDS
DURING THE AFTN HRS FROM THE NW AS MSTR SPILLS OVER TOP THE NRN
PERIPHERY OF THE RIDGE. ANOTHER FACTOR FOR INC HIGH CLOUDS IS UPR
LVL DIV DEPICTED BY NCEP MDLS THE SECOND HALF OF SUN. CU TRIGGER
TEMPS WILL BE IN THE UPR 70S AGAIN TMRW AND WE WILL SURPASS THOSE
NUMBERS BY LUNCH TIME...SO ANOTHER CU FIELD CAN BE ANTICIPATED.
TWEAKED INHERITED SKY GRIDS HOWEVER FOR A LARGE PART MID AND HIGH
CLOUDS WILL BE NON - OPAQUED SO ROLLING WITH ANOTHER MSNNY FCST.
NAM12BC GRIDS USED FOR MAXT SUN...WHILE MOSGUIDE BC USED FOR MINT
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
BENIGN WEATHER PERSISTS THROUGH MONDAY WITH MID-LVL HIGH PRESSURE
STILL IN CONTROL OF OUR WEATHER DESPITE ITS WESTWARD PROGRESSION.
BELT OF STRONGER H7-H5 WINDS MAKES STEERING FLOW NW...ALLOWING A
BAROCLINIC ZONE TO DROP THROUGH THE EMPIRE STATE INTO NRN PA BY
MON EVE. STILL THINK AMOUNT OF DRY AIR INDICATED BUT -1 STD PWATS
WILL ALLOW FOR ANOTHER PCPN FREE MONDAY...HWVR AMOUNT OF INCOMING
SOLAR RADIATION WILL BE DIMINISHED THROUGH THE DAY ESPECIALLY
ACROSS I-80 CORRIDOR. H8 TEMPS UNDER LIGHT SW WINDS IN THE BL
CLIMB TO 16C...WHICH WILL PUSH TEMPS INTO THE L-M 80S. THIS COULD
BE THE WARMEST DAY TO DATE OF THE ENTIRE MONTH IF WE HIT 85F AT
PIT...WHICH SOME STATISTICAL GUIDANCE SUGGESTS.
H5 ANTICYCLONE WILL STRENGTHEN THRU WED...LEAVING FCST AREA IN
NWLY FLOW ALOFT. SVRL SHRTWV TROFS WILL PROGRESS THRU THIS FLOW
DURG THE MON NGT-WED TIMEFRAME AS DP MSTR RETURNS TO THE RGN.
PRIMARY FACTOR INFLUENCING THE CVRG AND INTENSITY OF CNVCTN DURG
THIS TIME WILL BE MID-LVL LAPSE RATES. DYNAMICALLY...PATTERN WILL
BCM MORE FAVORABLE FOR SVR WX AS WIND FIELD STRENGTHENS. BOTH
ECMWF AND GFS DEPICT CNVCTN ASSOCIATED WITH WAVES PASSING THRU MON
EVE AND TUE AFTN-EVE. POPS WERE ADJUSTED APPROPRIATELY TO REFLECT
THIS PSBLTY.
ECMWF AND GFS DIFFER ON TIMING OF SHRTWV TROF ON WED. OWING TO
UNCERTAINTIES IN TIMING...HAVE NOT INCRD POPS CONSIDERABLY ON WED
OR MENTIONED SVR WX IN HWO. BUT THIS PSBLTY WILL NEED TO BE
MONITORED CLOSELY.
CONTD MAXIMA IN THE LOW-MID 80S XPCD THRU WED. MINIMA WILL INCR
MARKEDLY MON NGT AND TUE OWING TO LOW-LVL MSTR ADVCTN...WITH LOWS
IN THE MID-UPR 60S LKLY MANY AREAS TUE NGT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
BY LATE IN THE LONG TERM...UPPER-LEVEL RIDGE WILL SHIFT BACK TO
THE EAST AND SURFACE HIGH WILL TAKE OVER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR WITH LIGHT WINDS THROUGH THE PERIOD.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
A SERIES A SHORTWAVES MAY BRING RESTRICTIONS AT TIMES TUESDAY
THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
328 PM CDT FRI AUG 23 2013
.SYNOPSIS...
ISSUED AT 326 PM CDT FRI AUG 23 2013
RAP H5 ANALYSIS THIS AFTERNOON SHOWS HEIGHT RISES DOMINATING THE
CENTRAL CONUS...AS THE UPPER HIGH THAT WILL BE BRINGING US THE HEAT
WAVE COME SUNDAY IS STARTING TO STRENGTHEN OVER KANSAS...WITH THE
RIDGE AXIS BUILDING NORTH INTO THE RED RIVER VALLEY. WATER VAPOR
SHOWS A COUPLE OF WEAK WAVE ACROSS THE DAKOTAS THAT WILL BE
ROUNDING THE TOP OF THE RIDGE TONIGHT.
AT THE SFC...HIGH PRESSURE HAS NOW MOVED INTO THE GREAT LAKES...WITH
RETURN FLOW BECOMING ESTABLISHED ACROSS THE AREA. FRONT THAT SETTLED
ALONG THE IOWA BORDER THURSDAY HAS COMPLETELY WASHED OUT...WITH THE
HIGH DEWPOINTS THAT HAD POOLED OVER IOWA LAST NIGHT NOW SURGING
NORTH ON THE SOUTH WINDS...WITH CU FIELD MOVING NORTH OUT OF SRN MN
ALSO DENOTING WHERE DEWPOINT GO FROM THE 50S BACK UP TO THE UPPER
60S TO AROUND 70.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013
MAIN CONCERN RIGHT OFF THE BAT WILL BE THE POTENTIAL FOR
THUNDERSTORMS WITHIN THE NEXT COUPLE OF HOURS OVER SW MN. 19Z SPC
MESOANALYSIS SHOWS A BUBBLE OF 3000-4000 J/KG OF MLCAPE HAS
DEVELOPED IN THE MN/SD/NEB/IA BORDERS REGION. IN ADDITION...LLJ AND
ASSOCIATED MOISTURE TRANSPORT IS BEGINNING TO INCREASE ACROSS NE NEB
AND SE SODAK. IN THIS REGION...THE HRRR ALONG WITH ALL MEMBERS OF
THE 15Z HOPWRF SHOW AN AREA OF SCT TSTMS DEVELOPING AROUND SIOUX
FALLS...THEN DRIFTING NNE TOWARD THE UPPER MN RIVER VALLEY. HAVE
SOME ISO THUNDER WORDING OUT THERE BETWEEN 22 AND 02Z AS A RESULT.
INTERESTINGLY...BOTH THE HRRR AND HOPWRF SHOW THIS ACTIVITY BEING
DIURNALLY DRIVEN...WITH IT MOSTLY DISSIPATED BY 03Z.
FOR TONIGHT...STILL LOTS OF UNCERTAINTY AS TO HOW THINGS WILL UNFOLD
FOR PRECIP AS WE GET INTO A WAA REGIME...BUT IT IS STARTING TO LOOK
UNLIKELY THAT MUCH IS SEEN. LOOKING AT TEMP/MOISTURE ADVECTION
AROUND THE H7 LEVEL...THE GFS/NAM SHOW TWO AREAS OF ENHANCED FORCING
IN THE REGION TONIGHT...ONE DOWN ACROSS IOWA AND THE OTHER UP ACROSS
NRN MN. THE 23.12 ECMWF ONLY HAS THE NRN FORCING SOURCE. GIVEN THAT
THE NOSE OF THE LLJ LOOKS TO BE DIRECTED INTO NRN MN...CONFIDENCE IS
HIGHEST IN SOMETHING TRACKING ACROSS NRN MN /PER THE NMM AND SPCWRF
REFLECTIVITY FORECASTS/. HOWEVER...GIVEN THE BROAD ZONE OF
WAA/MOISTURE TRANSPORT MOVING ACROSS THE AREA CAN NOT RULE OUT
GETTING SOME AT LEAST SCT SHRA/TSRA AS THE LLJ WORKS ACROSS THE AREA
OVERNIGHT INTO SATURDAY MORNING. FOR THE POP GRIDS...DID NUDGE THEM
DOWN SOME...AND ALSO SLOWED DOWN THE ERN PROGRESSION OF
THINGS...CLOSER TO A NAM TIMING. DURING THE DAY ON SATURDAY...A
STRONG CAPPING INVERSION WILL BE MOVING IN...WHICH SHOULD SHUT DOWN
THE PRECIP FOR MOST OF MN BY THE AFTERNOON...WITH CHANCES LINGERING
ACROSS WRN WI.
LAST QUESTION MARK FOR THIS FORECAST IS HOW WARM DO WE GET ON
SATURDAY. THIS WILL DEPEND HIGHLY ON HOW QUICKLY SKIES CAN CLEAR OUT
FROM WEST TO EAST FROM THE MORNING INTO THE AFTERNOON. ERN MN/WRN WI
WILL LIKELY ENJOY THE CLOUD COVER FOR A GOOD CHUNK OF THE
DAY...WHICH SHOULD HELP HOLD HIGHS BACK INTO LOW/MID 80S...THOUGH
WITH DEWPS UP AROUND 70...IT WON`T EXACTLY FEEL COMFORTABLE. OUT IN
WRN MN...CLOUDS SHOULD CLEAR OUT EARLY ENOUGH TO ALLOW THE RETURN OF
90S...THOUGH DEPENDING ON HOW QUICKLY THE SUN ARRIVES...THE WEST
COULD SEE HIGHS ANYWHERE FROM THE UPPER 80S /MORE CLOUDS/ TO THE
UPPER 90S /VERY LITTLE CLOUD COVER/.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013
MAIN CONCERN IN THE EXTENDED IS WELL ADVERTISED HEAT WAVE THAT IS
FORECAST TO BRING NEAR RECORD TEMPERATURES BEGINNING SUNDAY...AND
LASTING THROUGH AT LEAST THE MIDDLE OF THIS WEEK. THE LONG DURATION
OF THIS HEAT...WITH THE WARM OVERNIGHT MIN TEMPS IS THE REASON
BEHIND THE EXCESSIVE HEAT WATCH THAT WAS ISSUED EARLIER THIS
MORNING. MASS TEMPERATURE FIELDS FROM THE H925/H850 LAYER...TOGETHER
WITH THE 500MB HEIGHTS SUPPORT THIS HEAT WATCH...BUT IF ANY DEBRIS
CLOUDS FROM AN OVERNIGHT MCS SPREAD ACROSS THE REGION...OR IF THE
MCS ITSELF BUILDS TO THE SOUTH AS INDICATED BY THE GFS AND ECMWF
23.12...THEN FORECAST MAX TEMPERATURES WILL BE OVERDONE BY SEVERAL
DEGREES.
AT THE START OF THE PERIOD LOW LEVEL WARM AIR ADVECTION WITH
SOUTHWEST FLOW WILL BE WELL ESTABLISHED ACROSS THE CWA...SO HAVE
RAISED MIN TEMPERATURES SATURDAY NIGHT/SUNDAY MORNING. ALSO HAVE
INCREASED THE WINDS HIGHER THAN GUIDANCE AS WELL...ESPECIALLY ALONG
THE UPPER MINNESOTA RIVER VALLEY WHERE THE DOWNSLOPE COMPONENT OFF
THE BUFFALO RIDGE WILL ADD A FEW EXTRA KNOTS. THESE WARMER LOW
TEMPERATURES WILL TRANSLATE INTO AFTERNOON HIGHS IN THE MID TO UPPER
90S ON SUNDAY AS THE BOUNDARY LAYER MIXES UP TO 850MB AS SHOWN VIA
THE BUFR SOUNDINGS. ANOTHER RESULT OF THIS DEEP MIXING WILL BE
DEWPOINT DROPPING INTO THE MID 60S DURING THE AFTERNOON. IF THE NAM
23.12 VERIFIES...DEWPOINTS COULD FALL INTO THE UPPER 50S AT A FEW
LOCATIONS. USED THE MIXDOWN TOOL TOGETHER WITH BIAS CORRECTED MODEL
BLEND TO POPULATE BOTH T AND TD ON SUNDAY. LOOKING AHEAD...INCREASED
LOW LEVEL MOISTURE WILL BRING HIGHER TDS ON MONDAY WITH AFTERNOON
MAX TEMPS ONCE AGAIN IN THE MID TO UPPER 90S.
THIS WILL BE THE TREND THROUGH THE EXTENDED...WITH THE ONCE CAVEAT
BEING THE CONVECTIVE POTENTIAL. AS ALLUDED TO EARLIER...OVERNIGHT
CONVECTION WILL DEVELOP AS SHORTWAVES PERIODICALLY ROUND THE BASE
OF THE UPPER LEVEL RIDGE ACROSS THE INTERNATIONAL BORDER. THE 23.12Z
GFS AND ECMWF DEVELOP CONVECTION ACROSS THE ARROWHEAD SATURDAY
NIGHT...AND OVER LAKE SUPERIOR SUNDAY NIGHT...WITH THE SECOND
FEATURE BUILDING SOUTHWEST AS IT IS FED BY THE LOW LEVEL JET. A
SHORTWAVE THAT IS CURRENTLY LOCATED OFF THE BAJA PENINSULA IS
FORECAST TO MOVE ACROSS THE UPPER MIDWEST MONDAY NIGHT...AND PUSH A
FRONTAL BOUNDARY THROUGH CENTRAL MN AND NORTHERN WI. THIS ALSO COULD
GIVE SOME REPRIEVE FROM THE HEAT BY MID WEEK...BUT CONFIDENCE IN THE
SOUTHERN EXTEND OF THIS FRONTAL BOUNDARY IS LOW AT THIS TIME.
THEREFORE FEEL THE POTENTIAL FOR DANGEROUS HEAT WAVE MERITS THE
EXCESSIVE HEAT WATCH IN CENTRAL MN AND FAR WESTERN WI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1238 PM CDT FRI AUG 23 2013
MOISTURE BEGINNING TO SURGE NORTH IN ERNEST...AS EVIDENCED BY CU
FIELD MOVING OUT OF SRN MN. MODEST INSTABILITY HAS DEVELOPED WITHIN
THIS MOIST PLUME OVER SRN MN...WITH THE HRRR CONTINUING TO
GENERATE AN AREA OF SCT TSTMS OVER SW MN THIS AFTERNOON. AS A
RESULT...INCLUDED A VCTS FOR RWF BETWEEN 22Z AND 01Z. STILL NOT
MUCH CONFIDENCE WITH HOW THINGS WILL UNFOLD TONIGHT INTO SATURDAY
MORNING WITH RESPECT TO TSTM CHANCES. BOTH THE NAM/GFS WARM AIR
AND MOISTURE ADVECTION AROUND 700 MB INDICATES A COUPLE OF AREAS
OF ENHANCED FORCING FOR TSTMS TONIGHT...ONE DOWN INTO IA AND THE
UP IN NRN MN...NICELY SPLITTING THE MPX AREA. BIG REASON FOR NOTHING
MORE THAN A VCSH MENTION STILL IS THAT BY THE END OF THE HOPWRF
AND HRRR /06Z TONIGHT/...NEITHER MODEL SHOWS ANYTHING DEVELOPING
NEAR MN/WI AT THAT POINT...VERY POSSIBLE THAT THIS BIT OF WARM
ADVECTION DOES NOT DO MUCH MORE THAN BRING IN A FIELD OF ACCUS.
CONFIDENCE IS BETTER WITH WINDS. LOW LEVEL WINDS ARE FORECAST TO
INCREASE DRAMATICALLY TONIGHT...AND ONCE MIXING PICKS UP ON
SATURDAY...SHOULD HAVE TO PROBLEM MIXING DOWN BETTER THAN 20 KT
GUSTS...WITH GUSTS OVER 30KTS NOT OUT OF THE QUESTION FOR WRN MN
BY THE AFTERNOON.
KMSP...LOW CONFIDENCE IN PRECIP POTENTIAL TONIGHT. AT THE VERY
LEAST...FAVORED THE LATER TIMING DEPICTED BY THE NAM. FOR WINDS
SATURDAY AFTERNOON...MIX DOWN TOOL ON THE NAM INDICATING GUSTS
OVER 30 KTS POSSIBLE DURING THE AFTERNOON...BUT THAT WILL BE
DEPENDENT IF WE CAN BREAK OUT INTO SOME SUNSHINE.
/OUTLOOK FOR KMSP/
SUN...VFR. SW WIND 10-15 G25 KT.
MON...VFR. SW WIND 10 KT.
TUE...VFR. SW WIND 5 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR MNZ047>051-054>070-073>078-082>085-091>093.
WI...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WIZ023-024.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 PM CDT FRI AUG 23 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT FRI AUG 23 2013
MOISTURE GRADIENT INDICATED EARLY THIS MORNING ACROSS IA...INTO
SD/FAR SW MN WHERE DEW PTS REMAIN IN THE 60S. THIS GRADIENT IS
MOST LIKELY THE REMNANTS OF THE OLD FRONTAL BOUNDARY THAT MOVED
INTO IA ON THURSDAY. IN ADDITION...DENSE FOG FORMED IN AREAS THAT
RECEIVED LOTS OF RAINFALL IN NE IA/SW WI. THIS AREA WILL LIKELY
MIX OUT AND DEEPEN THE MOISTURE ACROSS FAR SW/SC MN DURING THE DAY
AS WINDS SHIFT TO THE S/SE. DUE TO THIS MOISTURE GRADIENT AND THE
FACT THAT WINDS BEGIN TO INCREASE AND POOL IN SW MN...ISOLATED
TSRA WILL BE POSSIBLE...ESPECIALLY IF A SFC BOUNDARY DEVELOPS
WHICH IS LIKELY THE FORMATION OF THE WARM FRONT. SOME OF THE LOCAL
MODELS /HOPWRF/ HAVE ISOLATED REFLECTIVITY RETURNS ALONG THIS
MOISTURE GRADIENT THIS AFTN. THE BEST CHC/S OF RAINFALL WILL
DEVELOP LATER TONIGHT AS THE LLJ BEGINS TO INCREASE ACROSS
SD/IA/SW MN. THE PROXIMITY OF THIS LLJ...OR THE APEX OF THE JET
WILL BE THE FOCUS OF TSRA DEVELOPMENT. THE LOCATION REMAINS IN
QUESTION...BUT ENOUGH TRENDS IN THE SHORT TERM MODELS INDICATE
SOMEWHERE IN EASTERN SD/WC OR SW MN. ANY DEVIATION TO THIS JET
WILL LEAD TO THE DEVELOPMENT OF THE SHRA/TSRA FARTHER TO THE NORTH
OR SOUTH.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 333 AM CDT FRI AUG 23 2013
...SIGNIFICANT HEAT WAVE NEXT WEEK WITH RECORD-SETTING TEMPS POSSIBLE...
THE FOCUS IN THE LONG TERM PORTION OF THE FORECAST CONTINUES TO BE
ON HOT TEMPERATURES THROUGH MUCH OF THE UPCOMING WEEK. IN
FACT...IT COULD BE THE LONGEST DURATION OF CONSECUTIVE DAYTIME HIGH
TEMPERATURES IN THE MID 90S THAT MINNEAPOLIS HAS EXPERIENCED
DURING THE LAST WEEK OF AUGUST SINCE 1948.
PRIOR TO THE ARRIVAL OF THE HEAT...SATURDAY WILL FEATURE SCATTERED
SHOWERS AND THUNDERSTORMS LIFTING NORTHEAST ACROSS THE AREA DURING
THE MORNING...WITH AFTERNOON/EVENING CONVECTION PRIMARILY CONFINED
TO WEST CENTRAL WI ALONG/NORTH OF THE WARM FRONT.
BY SUNDAY...THE ENTIRE FORECAST AREA IS IN THE WARM SECTOR AHEAD
OF THE EASTERN DAKOTAS TROUGH. 925-850MB TEMPERATURES CLIMB TO
AROUND +27C TO +30C. WITH DEEP MIXING PROGGED TO ENSUE WITH BREEZY
SOUTH/SOUTHWEST WINDS...EXPECT LOW/MID 90S TO BE EASILY ACHIEVED.
SAID TEMPERATURES COMBINED WITH ANTICIPATED DEWPOINTS AROUND 70
DEGREES WOULD YIELD MAX HEAT INDEX VALUES OF 95-100
DEGREES...POSSIBLY EVEN A TAD HIGHER. ALTHOUGH THE DAYTIME
PRECIPITATION CHANCES WILL BE DISPLACED TO THE NORTH OF THE
FORECAST AREA...COULD SEE WIDELY SCATTERED ACTIVITY IN CENTRAL
MN/WI ON SUNDAY NIGHT INTO MONDAY AS THE TROUGH SAGS INTO THE
AREA.
THE THERMAL RIDGE HOLDS FIRMLY IN PLACE ACROSS THE FORECAST AREA
FROM MONDAY THROUGH THURSDAY PER THE GFS...WHICH WOULD MEAN
CONTINUANCE OF HIGHS IN THE MID 90S. HOWEVER...THE 00Z ECMWF
DIFFERED NOTABLY...IN THAT IT REDUCED HEIGHTS/TEMPS FOR WEDNESDAY
AND THURSDAY /YIELDING HIGHS IN THE 80S/. THEREFORE HAVE A TINGE
OF LOWERED CONFIDENCE THAT WE/D MEET HEAT ADVISORY CRITERIA FOR
THE 4+ CONSECUTIVE DAYS NEEDED TO WARRANT AN EXCESSIVE HEAT
WATCH/WARNING. WILL CONTINUE TO HIGHLIGHT THE EXCESSIVE HEAT
THREAT IN THE HWO...AND SEE IF THE 12Z ECMWF TREND CONTINUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1238 PM CDT FRI AUG 23 2013
MOISTURE BEGINNING TO SURGE NORTH IN ERNEST...AS EVIDENCED BY CU
FIELD MOVING OUT OF SRN MN. MODEST INSTABILITY HAS DEVELOPED WITHIN
THIS MOIST PLUME OVER SRN MN...WITH THE HRRR CONTINUING TO
GENERATE AN AREA OF SCT TSTMS OVER SW MN THIS AFTERNOON. AS A
RESULT...INCLUDED A VCTS FOR RWF BETWEEN 22Z AND 01Z. STILL NOT
MUCH CONFIDENCE WITH HOW THINGS WILL UNFOLD TONIGHT INTO SATURDAY
MORNING WITH RESPECT TO TSTM CHANCES. BOTH THE NAM/GFS WARM AIR
AND MOISTURE ADVECTION AROUND 700 MB INDICATES A COUPLE OF AREAS
OF ENHANCED FORCING FOR TSTMS TONIGHT...ONE DOWN INTO IA AND THE
UP IN NRN MN...NICELY SPLITTING THE MPX AREA. BIG REASON FOR NOTHING
MORE THAN A VCSH MENTION STILL IS THAT BY THE END OF THE HOPWRF
AND HRRR /06Z TONIGHT/...NEITHER MODEL SHOWS ANYTHING DEVELOPING
NEAR MN/WI AT THAT POINT...VERY POSSIBLE THAT THIS BIT OF WARM
ADVECTION DOES NOT DO MUCH MORE THAN BRING IN A FIELD OF ACCUS.
CONFIDENCE IS BETTER WITH WINDS. LOW LEVEL WINDS ARE FORECAST TO
INCREASE DRAMATICALLY TONIGHT...AND ONCE MIXING PICKS UP ON
SATURDAY...SHOULD HAVE TO PROBLEM MIXING DOWN BETTER THAN 20 KT
GUSTS...WITH GUSTS OVER 30KTS NOT OUT OF THE QUESTION FOR WRN MN
BY THE AFTERNOON.
KMSP...LOW CONFIDENCE IN PRECIP POTENTIAL TONIGHT. AT THE VERY
LEAST...FAVORED THE LATER TIMING DEPICTED BY THE NAM. FOR WINDS
SATURDAY AFTERNOON...MIX DOWN TOOL ON THE NAM INDICATING GUSTS
OVER 30 KTS POSSIBLE DURING THE AFTERNOON...BUT THAT WILL BE
DEPENDENT IF WE CAN BREAK OUT INTO SOME SUNSHINE.
/OUTLOOK FOR KMSP/
SUN...VFR. SW WIND 10-15 G25 KT.
MON...VFR. SW WIND 10 KT.
TUE...VFR. SW WIND 5 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR MNZ047>051-054>070-073>078-082>085-091>093.
WI...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WIZ023-024.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
825 PM MDT SAT AUG 24 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
EVENING UPDATE...
CHANGE FOR THIS EVENING WAS TO REASSESS POPS AND SPREAD
MENTIONABLE SLIGHT CHANCE ACROSS A LARGER SECTION OF THE CWA.
CURRENTLY WITH THE STATIONARY BOUNDARY HOVERING OVER THE AREA... A
FOCAL POINT WITH SOME VORTICITY HAS DEVELOPED FOR ANY MONSOONAL
MOISTURE TO GENERATE RAIN SHOWERS OR A THUNDERSTORM OR TWO
OVERNIGHT. A FEW SHOWERS ARE CROSSING THE MISSOURI RIVER FROM
FERGUS TO PHILLIPS COUNTY AS OF 8PM ON RADAR AND HRRR MODEL DOES
HAVE SOME WEAK NOCTURNAL DEVELOPMENT AS WELL. GAH
PREVIOUS SHORT TERM DISCUSSION...
A BROAD AREA OF HIGH PRESSURE OVER CENTRAL CONUS WILL MAINTAIN A
PERSISTENT SOUTHWEST FLOW ALOFT OVER NORTHEAST MONTANA THROUGH THE
SHORT TERM PERIOD. WITH 700MB TEMPERATURES STAYING ABOVE 10C AND
THICKNESS HEIGHTS AROUND 580DM...SURFACE HIGHS WILL CONTINUE INTO
THE 90S AND OVERNIGHT LOWS IN THE 60S.
TONIGHT...A WEAK SHORTWAVE EMBEDDED IN THE FLOW ALOFT WILL
UNDERCUT THE CWA WITH SOME ENERGY THAT WILL LIKELY PRODUCE STORMS
TO OUR SOUTH AND EAST...AND POSSIBLY OUR SOUTHEAST CORNER.
SUNDAY...SURFACE WINDS SHIFT TO THE SOUTHWEST AND THERMAL RIDGING
WILL RAMP HIGHS UP INTO THE MID TO UPPER 90S FOR A HOT DAY. THERE
IS SOME WEAK SURFACE BASED INSTABILITY AT 18Z THAT DISAPPEARS BY
00Z. SO WILL ONLY MAINTAIN SLIGHT CHANCE FOR ISOLATED THUNDER. SPC
MAINTAINS MOST OF OUR CWA UNDER ITS CONVECTIVE OUTLOOK FOR GENERAL
THUNDERSTORMS.
SUNDAY NIGHT AND MONDAY...A SHORTWAVE DISTURBANCE MOVING THROUGH
CENTRAL ALBERTA WILL NUDGE THE STATIONARY BOUNDARY SOUTHEAST A
BIT WHICH WILL GIVE THE OVERRUNNING MOISTURE PLUME SOMETHING TO
FOCUS ON. THE MOISTURE PLUME CONTINUES TO BE FROM AN AREA OFF THE
COAST OF SOUTHERN AND BAJA CALIFORNIA. THEREFORE WITH THIS
ADDITIONAL MOISTURE THERE IS AN INCREASED CHANCE FOR
THUNDERSTORMS IN A BAND FROM SOUTHWEST MONTANA THROUGH CENTRAL
MONTANA...POSSIBLY CLIPPING OUR WESTERN ZONES OVERNIGHT. THE
BOUNDARY SAGS FROM THE NORTH ON MONDAY SO THE FAVORED AREA FOR
STORMS WILL BE ALONG AND NORTH THE INTERNATIONAL BORDER. SOUTH OF
THIS BOUNDARY THE HOT CONDITIONS OF SUNDAY WILL CONTINUE INTO
MONDAY. HIGHS ARE EXPECTED WELL INTO THE MID TO UPPER 90S AGAIN.
ANOTHER EMBEDDED SHORTWAVE AND ENHANCE VORTICITY WILL CREATE
CONDITIONS FOR A CHANCE OF THUNDER ON MONDAY. SCT
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
MADE SOME MINOR ADJUSTMENTS...ESPECIALLY WHERE BETTER MODEL
AGREEMENT WAS EVIDENT FOR POPS...WX...ETC.
THE WARM INFLUENCE OF THE WESTERN AND CENTRAL STATES RIDGE SEEMS
TO BE IN PLACE OVER OUR CWA FOR THE DURATION OF THE EXTENDED
FORECAST PERIOD. ALTHOUGH...JUST BEYOND THE FORECAST PERIOD...A
STRONG COLD FRONT AND STORM SYSTEM SEEMS POISED TO PUSH THROUGH
THE REGION FROM THE NORTHWEST.
UNTIL THEN...EXPECT GENERAL SOUTHWESTERLY FLOW ALOFT WITH
OCCASIONAL EMBEDDED SHORT WAVE DISTURBANCES. AT THIS TIME...MODELS
ARE INDICATING THAT THESE PERIODS OF BETTER CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL CENTER AROUND WEDNESDAY. THAT BEING
SAID...THE CENTRAL PLAINS RIDGE OF HIGH PRESSURE WILL BE VERY
LARGE AND INFLUENTIAL AND MAY KEEP ANY SHORT WAVE DISTURBANCE
PUSHED JUST WEST AND AWAY FROM OUR CWA. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...
UPPER RIDGE OVER THE CENTRAL CONUS WITH TROF OFF THE WEST COAST
DOMINATES THE PATTERN FOR MOST OF THE EXTENDED PERIOD. SOUTHWEST
FLOW INTO MONTANA WILL CONTINUE TO PUMP VERY HOT AIR NORTHWARD
RESULTING IN WELL ABOVE NORMAL TEMPERATURES THROUGH THE END OF THE
MONTH.
POSITION OF THE UPPER RIDGE SUGGEST THAT MONSOONAL MOISTURE PLUME
WILL BE REDIRECTED EASTWARD BEFORE REACHING NORTHEAST MONTANA WITH
WEST COAST TROF DRAWING A WEDGE OF DRY AIR INTO THE STATE.
SHORTWAVE LIFTING OUT OF THE GREAT BASIN ON WEDNESDAY WILL
INTERRUPT THIS MOISTURE PATTERN ALLOWING FOR SOME THUNDERSTORM
DEVELOPMENT.
BY THE END OF THE WEEK MODELS SUGGEST THE SUPPRESSION OF THE UPPER
RIDGE WITH THE WEST COAST TROF BEGINNING TO PUSH EAST. STILL
SIGNIFICANT MODEL DIFFERENCES ON HOW OR WHEN THIS WILL HAPPEN BUT
EXPECT COOLING TEMPERATURES AND SOME POTENTIAL FOR THUNDERSTORMS
WHEN IT DOES. EBERT
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL FOR ALL TAF SITES THROUGHOUT MOST OF
THIS TAF CYCLE. AN ISOLATED THUNDERSTORM MAY IMPACT A TAF SITE
OVERNIGHT AND AGAIN SUNDAY AFTERNOON AND EVENING. WINDS WILL BE
LIGHT AND VARIABLE OVERNIGHT AND BECOME SOUTHERLY WINDS AROUND 10
KNOTS BY MIDDAY SUNDAY.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 539 AM CDT FRI AUG 23 2013
LATEST HRRR AND 06Z GFS ARE COMING IN WETTER TODAY...WHICH IS ALSO
BEING BACKED UP BY RADAR TRENDS THAT SHOW INCREASING CONVECTIVE
ACTIVITY ACROSS PORTIONS OF OUR FORECAST AREA. SHOWERS AND
THUNDERSTORMS REMAIN FAIRLY ISOLATED...BUT MAY LINGER LONGER THIS
MORNING THAN ORIGINALLY ANTICIPATED. IN ADDITION...THESE LATEST
MODEL RUNS ARE MORE BULLISH ON SEEING AFTERNOON REDEVELOPMENT AND
THUS WE MAY NEED TO EVENTUALLY INCLUDE POPS FOR THIS AFTERNOON IF
12Z MODEL RUNS CONTINUE TO TREND TOWARDS NEEDING PRECIPITATION
CHANCES.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI AUG 23 2013
THE MAIN FORECAST CONCERN THROUGH THE SHORT TERM PERIOD WILL
CENTER AROUND THE CHANCE OF RAIN EARLY THIS MORNING...PRIMARILY
ACROSS NORTH CENTRAL KANSAS.
THERE IS A WEAK SHORT WAVE OVER NORTHEAST COLORADO EARLY THIS
MORNING THAT WILL TRACK EAST TODAY ACROSS SOUTHERN NEBRASKA. IN
ADDITION...THERE IS A MODEST 850MB JET MAX LOCATED OVER WESTERN
KANSAS TO THE EAST OF AN EASTERN COLORADO MCS. NEW THUNDERSTORMS
HAVE BEEN FORMING WITHIN THIS LOW LEVEL JET REGION OUT AHEAD OF
THE WEAKENING COLORADO MCS. HAVE ADDED POPS ACROSS KANSAS ZONES
DUE TO THE DEVELOPING SHOWERS AND THUNDERSTORMS. BELIEVE THESE
SHOWERS/THUNDERSTORMS WILL REMAIN FAIRLY ISOLATED AND WILL BEGIN
TO DIE OFF BY AROUND OR JUST AFTER SUNRISE AS THE LOW LEVEL JET
GRADUALLY DECREASES. THESE SHOWERS ARE NOT BEING WELL MODELED AND
SO CONFIDENCE IN WHEN THE CONVECTION WILL FINALLY DIE DOWN IS
RATHER MARGINAL.
THERE IS SOME POSSIBILITY OF AFTERNOON SHOWERS AND THUNDERSTORMS
DESPITE OUR CURRENTLY DRY FORECAST. THE 00Z AND 06Z NAM BOTH TRY
TO RE-INITIATE CONVECTION LATE THIS AFTERNOON JUST TO OUR WEST IN
ASSOCIATION WITH THE WEAK SHORT WAVE AS IT TRACKS EAST ACROSS
NEBRASKA. IN ADDITION...SOME WRF MODELS ALSO INDICATE THE
POSSIBILITY OF AFTERNOON CONVECTION ACROSS PORTIONS OF OUR FORECAST
AREA. HOWEVER...EXPECT INCREASING TEMPERATURES WITHIN A CAPPING
INVERSION AS WIND AT 700MB TURNS SOUTHWEST AND WARMER AIR MOVES IN
ALOFT. THE WRF HAS BEEN OVERDOING CONVECTION RECENTLY AND BELIEVE
THAT THE THREAT OF AFTERNOON REDEVELOPMENT IS FAIRLY LOW GIVEN THE
STRENGTHENING CAP. THEREFORE...HAVE ELECTED TO CONTINUE TO CARRY
A DRY FORECAST ACROSS OUR CWA THIS AFTERNOON.
HIGH TEMPERATURES TODAY SHOULD BE WARMER AS OUR WIND WILL BE MORE
SOUTHERLY TODAY AND TEMPERATURES WILL BE WARMING AT MOST ALL
LAYERS OF THE LOWER ATMOSPHERE. HOWEVER...MID TO HIGH
CLOUDS...ESPECIALLY THIS MORNING COULD TAMPER THE WARM UP AND
WILL GO FOR HIGHS RANGING FROM THE UPPER 80S ACROSS NEBRASKA TO
THE 90S ACROSS KANSAS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI AUG 23 2013
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM PERIOD LIES WITH
TEMPERATURES.
MODELS ARE IN GOOD AGREEMENT AT THE START OF THE FORECAST
PERIOD...SHOWING UPPER LEVEL HIGH PRESSURE CENTERED OVER ERN OK/KS
INTO MISSOURI...WITH AN AREA OF LOW PRESSURE SPINNING JUST OFF THE
PAC NW COAST AND TROUGH AXIS EXTENDING SOUTH OFF THE WEST COAST.
THE WEAK WAVE PASSING THROUGH THE FLOW STILL LOOKS TO REMAIN FAR
ENOUGH NORTH NOT TO HAVE AN IMPACT ON THE CWA. THROUGH THE REST OF
THE WEEKEND AND RIGHT ON INTO THE WORK WEEK...GOOD AGREEMENT
CONTINUES BETWEEN MODELS WITH THE OVERALL PATTERN...AND THE DRY
FORECAST REMAINS. THE UPPER LEVEL RIDGE...ESP DURING THE WORK
WEEK...WILL ACTUALLY SLIDE A TOUCH TO THE WEST AS AN UPPER LEVEL
DISTURBANCE/TROUGHING DIGS A BIT FURTHER SOUTH TOWARD THE EAST
COAST. THIS LOOKS TO PLACE THE UPPER LEVEL HIGH MORE SQUARELY OVER
THE AREA...CENTERED OVER KS/PERHAPS NEAR THE KS/NE STATE LINE. ANY
DISTURBANCES WOULD SLIDE NORTH OF THE CWA...WITH THE ATMOSPHERE WELL
CAPPED.
AT THE SURFACE...THE GENERAL PATTERN WILL RESULT IN SOUTHERLY WINDS
THROUGH THE ENTIRE FORECAST PERIOD...AS A TROUGH LIES OVER THE HIGH
PLAINS WITH WEAK HIGH PRESSURE OFF TO THE EAST. THE WEEKEND LOOKS
TO BE BREEZY...ESP SATURDAY...WITH A TIGHTER PRESSURE GRADIENT
EXPECTED TO DEVELOP...POTENTIALLY BRINGING SUSTAINED SPEEDS IN THE
20 TO 25 MPH RANGE WITH HIGHER GUSTS.
AS FAR AS TEMPERATURES GO...WITH MODELS SHOWING 850MB TEMPS
INCREASING INTO THE MID/UPPER 20C RANGE...HIGH TEMPERATURES CWA-WIDE
IN THE 90S DONT LOOK TO BE GOING AWAY ANY TIME SOON. ALSO CANT
COMPLETELY RULE OUT SOME READINGS NEAR THE 100 DEGREE MARK...ESP IN
SWRN LOCATION.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI AUG 23 2013
THE MAIN FORECAST CONCERN THROUGH THE SHORT TERM PERIOD WILL
CENTER AROUND THE CHANCE OF RAIN EARLY THIS MORNING...PRIMARILY
ACROSS NORTH CENTRAL KANSAS.
THERE IS A WEAK SHORT WAVE OVER NORTHEAST COLORADO EARLY THIS
MORNING THAT WILL TRACK EAST TODAY ACROSS SOUTHERN NEBRASKA. IN
ADDITION...THERE IS A MODEST 850MB JET MAX LOCATED OVER WESTERN
KANSAS TO THE EAST OF AN EASTERN COLORADO MCS. NEW THUNDERSTORMS
HAVE BEEN FORMING WITHIN THIS LOW LEVEL JET REGION OUT AHEAD OF
THE WEAKENING COLORADO MCS. HAVE ADDED POPS ACROSS KANSAS ZONES
DUE TO THE DEVELOPING SHOWERS AND THUNDERSTORMS. BELIEVE THESE
SHOWERS/THUNDERSTORMS WILL REMAIN FAIRLY ISOLATED AND WILL BEGIN
TO DIE OFF BY AROUND OR JUST AFTER SUNRISE AS THE LOW LEVEL JET
GRADUALLY DECREASES. THESE SHOWERS ARE NOT BEING WELL MODELED AND
SO CONFIDENCE IN WHEN THE CONVECTION WILL FINALLY DIE DOWN IS
RATHER MARGINAL.
THERE IS SOME POSSIBILITY OF AFTERNOON SHOWERS AND THUNDERSTORMS
DESPITE OUR CURRENTLY DRY FORECAST. THE 00Z AND 06Z NAM BOTH TRY
TO RE-INITIATE CONVECTION LATE THIS AFTERNOON JUST TO OUR WEST IN
ASSOCIATION WITH THE WEAK SHORT WAVE AS IT TRACKS EAST ACROSS
NEBRASKA. IN ADDITION...SOME WRF MODELS ALSO INDICATE THE
POSSIBILITY OF AFTERNOON CONVECTION ACROSS PORTIONS OF OUR FORECAST
AREA. HOWEVER...EXPECT INCREASING TEMPERATURES WITHIN A CAPPING
INVERSION AS WIND AT 700MB TURNS SOUTHWEST AND WARMER AIR MOVES IN
ALOFT. THE WRF HAS BEEN OVERDOING CONVECTION RECENTLY AND BELIEVE
THAT THE THREAT OF AFTERNOON REDEVELOPMENT IS FAIRLY LOW GIVEN THE
STRENGTHENING CAP. THEREFORE...HAVE ELECTED TO CONTINUE TO CARRY
A DRY FORECAST ACROSS OUR CWA THIS AFTERNOON.
HIGH TEMPERATURES TODAY SHOULD BE WARMER AS OUR WIND WILL BE MORE
SOUTHERLY TODAY AND TEMPERATURES WILL BE WARMING AT MOST ALL
LAYERS OF THE LOWER ATMOSPHERE. HOWEVER...MID TO HIGH
CLOUDS...ESPECIALLY THIS MORNING COULD TAMPER THE WARM UP AND
WILL GO FOR HIGHS RANGING FROM THE UPPER 80S ACROSS NEBRASKA TO
THE 90S ACROSS KANSAS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI AUG 23 2013
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM PERIOD LIES WITH
TEMPERATURES.
MODELS ARE IN GOOD AGREEMENT AT THE START OF THE FORECAST
PERIOD...SHOWING UPPER LEVEL HIGH PRESSURE CENTERED OVER ERN OK/KS
INTO MISSOURI...WITH AN AREA OF LOW PRESSURE SPINNING JUST OFF THE
PAC NW COAST AND TROUGH AXIS EXTENDING SOUTH OFF THE WEST COAST.
THE WEAK WAVE PASSING THROUGH THE FLOW STILL LOOKS TO REMAIN FAR
ENOUGH NORTH NOT TO HAVE AN IMPACT ON THE CWA. THROUGH THE REST OF
THE WEEKEND AND RIGHT ON INTO THE WORK WEEK...GOOD AGREEMENT
CONTINUES BETWEEN MODELS WITH THE OVERALL PATTERN...AND THE DRY
FORECAST REMAINS. THE UPPER LEVEL RIDGE...ESP DURING THE WORK
WEEK...WILL ACTUALLY SLIDE A TOUCH TO THE WEST AS AN UPPER LEVEL
DISTURBANCE/TROUGHING DIGS A BIT FURTHER SOUTH TOWARD THE EAST
COAST. THIS LOOKS TO PLACE THE UPPER LEVEL HIGH MORE SQUARELY OVER
THE AREA...CENTERED OVER KS/PERHAPS NEAR THE KS/NE STATE LINE. ANY
DISTURBANCES WOULD SLIDE NORTH OF THE CWA...WITH THE ATMOSPHERE WELL
CAPPED.
AT THE SURFACE...THE GENERAL PATTERN WILL RESULT IN SOUTHERLY WINDS
THROUGH THE ENTIRE FORECAST PERIOD...AS A TROUGH LIES OVER THE HIGH
PLAINS WITH WEAK HIGH PRESSURE OFF TO THE EAST. THE WEEKEND LOOKS
TO BE BREEZY...ESP SATURDAY...WITH A TIGHTER PRESSURE GRADIENT
EXPECTED TO DEVELOP...POTENTIALLY BRINGING SUSTAINED SPEEDS IN THE
20 TO 25 MPH RANGE WITH HIGHER GUSTS.
AS FAR AS TEMPERATURES GO...WITH MODELS SHOWING 850MB TEMPS
INCREASING INTO THE MID/UPPER 20C RANGE...HIGH TEMPERATURES CWA-WIDE
IN THE 90S DONT LOOK TO BE GOING AWAY ANY TIME SOON. ALSO CANT
COMPLETELY RULE OUT SOME READINGS NEAR THE 100 DEGREE MARK...ESP IN
SWRN LOCATION.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM CDT FRI AUG 23 2013
PREVAILING VFR CONDITIONS WILL CONTINUE AT KGRI FOR THE NEXT 24
HOURS...WITH OCCASIONALLY GUSTY SOUTHERLY WINDS CONTINUING
THROUGHOUT. EXPECT A LINE OF STORMS STARTING TO DEVELOP ON
SATELLITE NEAR LBF...TO CONTINUE TO BUILD AND SHIFT EAST...BUT
MODEL GUIDANCE IS NOT PICKING UP ON THIS WELL. LATEST RAP/12Z WRF
ARE TRYING TO DEVELOP SOME CONVECTION AND LIFT IT NORTHEAST
THROUGH THE LATE AFTERNOON HOURS...BUT EVEN SO...CONFIDENCE IS LOW
DUE TO THE DIFFERENCES BETWEEN CURRENT RETURNS AND MODEL DATA THAT
IS TRYING TO CAPTURE THIS. LATEST SPC MESO ANALYSIS DOES SHOW
MODERATE INSTABILITY BUILDING AHEAD OF THIS LINE...SO DO THINK WE
COULD SEE SOME SHRA OR TSRA IN THE VICINITY OF KGRI AS EARLY AS
22Z...BUT WITH CONFIDENCE LOW...DECIDED TO ONLY GO WITH A CB FOR
THE TIME BEING. OTHERWISE...ONCE THIS BOUNDARY SHIFTS
EAST...CLEARING SKIES AND GUSTY SOUTHERLY WINDS WILL PERSIST
THROUGH THE END OF THE VALID TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...ADO
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1221 PM CDT FRI AUG 23 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE. SOUTHEAST WINDS
AT 10-14KT SHOULD MAINTAIN SPEEDS FOR MOST OF TONIGHT...WITH WINDS
INCREASING OUT OF THE SOUTH BY MID-MORNING TO AROUND 15-19KT. SOME
INTERMITTENT MID-LEVEL CLOUDS ARE POSSIBLE. COULD SEE A FEW
SHOWERS IN NORTHEAST NEB TONIGHT...MAINLY NEAR KOFK...BUT HAVE
KEPT MENTION OF TAFS FOR NOW DUE TO LOW CONFIDENCE IN COVERAGE.
MAYES
&&
.PREV DISCUSSION... /ISSUED 932 AM CDT FRI AUG 23 2013/
DISCUSSION...
UPDATED GRIDS THIS MORNING FOR ONGOING VERY ISOLATED SHOWERS.
INCREASED THE DURATION FOR THE REST OF THE MORNING AS SHOWERS ARE
HANGING IN THERE. RAP INDICATES BOTH MID-LEVEL LAPSE RATES AND
MUCAPE ARE RATHER LIMITED ACROSS THE AREA...AND WITH NO LIGHTNING
YET IN THIS ACTIVITY...HAVE REMOVED THUNDER MENTION FOR TODAY.
ALSO INCREASED SKY COVER WITH BROKEN TO OVERCAST SKIES OVER MOST
OF THE CWA. CHANCE OF SHOWERS...WITH MAYBE AN ISOLATED RUMBLE OF
THUNDER...DOES RETURN TONIGHT AS THE LOW-LEVEL JET PICKS UP...MOST
LIKELY TO THE NORTHERN CWA...BUT LIKELY WILL BE A BREAK BETWEEN
THE ONGOING SHOWERS AND THE OVERNIGHT ACTIVITY.
MAYES
PREV DISCUSSION... /ISSUED 349 AM CDT FRI AUG 23 2013/
DISCUSSION...
STRONG UPPER LEVEL RIDGING WILL DOMINATE THE WEATHER PATTERN FOR
NEXT SEVERAL DAYS. THIS WILL KEEP PRECIPITATION CHANCES MEAGER AND
TEMPERATURES SOME 8 TO 10 DEGREES ABOVE NORMAL.
TODAY AND TONIGHT...THE MAIN FORECAST CONCERN FOR THIS PERIOD WILL
BE THE CHANCE FOR PRECIPITATION THIS MORNING AND AGAIN TONIGHT.
THE LATEST 88D SCANS SHOW SOME LIGHT SHOWERS ARE DEVELOPING ALONG
THE SOUTHEAST NEBRASKA/KANSAS BORDER. THESE SHOWERS SHOULDN`T
AMOUNT TO MUCH AND ARE FORCED BY WEAK WARM AIR ADVECTION ALOFT.
DECIDED TO MAINTAIN SLIGHT CHANCE POPS THROUGH MID MORNING TO
ACCOUNT FOR THIS. FOR TONIGHT...A STRENGTHENING LOW LEVEL JET AND
850MB FRONT WILL ACT TO GENERATE PRECIPITATION ACROSS MUCH OF
EASTERN SOUTH DAKOTA...WHICH MAY BRUSH THE NORTHERN HALF OF THE
COUNTY WARNING AREA.
SATURDAY ONWARD...SOME COMPUTER MODELS WANT TO MAINTAIN SOME OF
THE OVERNIGHT PRECIPITATION INTO WESTERN IOWA ON SATURDAY
MORNING. IT DOESN`T APPEAR THERE IS MUCH FORCING TO SUPPORT THIS.
IN FACT 500MB HEIGHTS ARE ON THE RISE...SO WENT WITH A DRY
FORECAST FROM SATURDAY ONWARD. TEMPERATURES WILL REMAIN WARM...LOW
TO MID 90S...THROUGH THE REST OF THE FORECAST. WITH DEW POINTS
REMAINING STEADY IN THE MID TO UPPER 60S APPARENT TEMPERATURES
WILL PUSH 100...WHICH IS BELOW HEAT ADVISORY CRITERIA.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
932 AM CDT FRI AUG 23 2013
.DISCUSSION...
UPDATED GRIDS THIS MORNING FOR ONGOING VERY ISOLATED SHOWERS.
INCREASED THE DURATION FOR THE REST OF THE MORNING AS SHOWERS ARE
HANGING IN THERE. RAP INDICATES BOTH MID-LEVEL LAPSE RATES AND
MUCAPE ARE RATHER LIMITED ACROSS THE AREA...AND WITH NO LIGHTNING
YET IN THIS ACTIVITY...HAVE REMOVED THUNDER MENTION FOR TODAY.
ALSO INCREASED SKY COVER WITH BROKEN TO OVERCAST SKIES OVER MOST
OF THE CWA. CHANCE OF SHOWERS...WITH MAYBE AN ISOLATED RUMBLE OF
THUNDER...DOES RETURN TONIGHT AS THE LOW-LEVEL JET PICKS UP...MOST
LIKELY TO THE NORTHERN CWA...BUT LIKELY WILL BE A BREAK BETWEEN
THE ONGOING SHOWERS AND THE OVERNIGHT ACTIVITY.
MAYES
&&
.PREV DISCUSSION... /ISSUED 632 AM CDT FRI AUG 23 2013/
AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE TAF CYCLE. A FEW
ISOLATED SHOWERS ARE FLOATING AROUND THE AREA THIS MORNING BUT
SHOULD REMAIN ISOLATED ENOUGH TO LEAVE A MENTION OUT OF THE TAFS.
EXPECT MORE SCATTERED ACTIVITY TO DEVELOP TOWARD THE END OF THE
TAF CYCLE SATURDAY MORNING...BUT DUE TO LACK OF COVERAGE...WILL
KEEP OUT OF THIS SET OF TAFS.
KERN
PREV DISCUSSION... /ISSUED 349 AM CDT FRI AUG 23 2013/
DISCUSSION...
STRONG UPPER LEVEL RIDGING WILL DOMINATE THE WEATHER PATTERN FOR
NEXT SEVERAL DAYS. THIS WILL KEEP PRECIPITATION CHANCES MEAGER AND
TEMPERATURES SOME 8 TO 10 DEGREES ABOVE NORMAL.
TODAY AND TONIGHT...THE MAIN FORECAST CONCERN FOR THIS PERIOD WILL
BE THE CHANCE FOR PRECIPITATION THIS MORNING AND AGAIN TONIGHT.
THE LATEST 88D SCANS SHOW SOME LIGHT SHOWERS ARE DEVELOPING ALONG
THE SOUTHEAST NEBRASKA/KANSAS BORDER. THESE SHOWERS SHOULDN`T
AMOUNT TO MUCH AND ARE FORCED BY WEAK WARM AIR ADVECTION ALOFT.
DECIDED TO MAINTAIN SLIGHT CHANCE POPS THROUGH MID MORNING TO
ACCOUNT FOR THIS. FOR TONIGHT...A STRENGTHENING LOW LEVEL JET AND
850MB FRONT WILL ACT TO GENERATE PRECIPITATION ACROSS MUCH OF
EASTERN SOUTH DAKOTA...WHICH MAY BRUSH THE NORTHERN HALF OF THE
COUNTY WARNING AREA.
SATURDAY ONWARD...SOME COMPUTER MODELS WANT TO MAINTAIN SOME OF
THE OVERNIGHT PRECIPITATION INTO WESTERN IOWA ON SATURDAY
MORNING. IT DOESN`T APPEAR THERE IS MUCH FORCING TO SUPPORT THIS.
IN FACT 500MB HEIGHTS ARE ON THE RISE...SO WENT WITH A DRY
FORECAST FROM SATURDAY ONWARD. TEMPERATURES WILL REMAIN WARM...LOW
TO MID 90S...THROUGH THE REST OF THE FORECAST. WITH DEW POINTS
REMAINING STEADY IN THE MID TO UPPER 60S APPARENT TEMPERATURES
WILL PUSH 100...WHICH IS BELOW HEAT ADVISORY CRITERIA.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
546 AM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 539 AM CDT FRI AUG 23 2013
LATEST HRRR AND 06Z GFS ARE COMING IN WETTER TODAY...WHICH IS ALSO
BEING BACKED UP BY RADAR TRENDS THAT SHOW INCREASING CONVECTIVE
ACTIVITY ACROSS PORTIONS OF OUR FORECAST AREA. SHOWERS AND
THUNDERSTORMS REMAIN FAIRLY ISOLATED...BUT MAY LINGER LONGER THIS
MORNING THAN ORIGINALLY ANTICIPATED. IN ADDITION...THESE LATEST
MODEL RUNS ARE MORE BULLISH ON SEEING AFTERNOON REDEVELOPMENT AND
THUS WE MAY NEED TO EVENTUALLY INCLUDE POPS FOR THIS AFTERNOON IF
12Z MODEL RUNS CONTINUE TO TREND TOWARDS NEEDING PRECIPITATION
CHANCES.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI AUG 23 2013
THE MAIN FORECAST CONCERN THROUGH THE SHORT TERM PERIOD WILL
CENTER AROUND THE CHANCE OF RAIN EARLY THIS MORNING...PRIMARILY
ACROSS NORTH CENTRAL KANSAS.
THERE IS A WEAK SHORT WAVE OVER NORTHEAST COLORADO EARLY THIS
MORNING THAT WILL TRACK EAST TODAY ACROSS SOUTHERN NEBRASKA. IN
ADDITION...THERE IS A MODEST 850MB JET MAX LOCATED OVER WESTERN
KANSAS TO THE EAST OF AN EASTERN COLORADO MCS. NEW THUNDERSTORMS
HAVE BEEN FORMING WITHIN THIS LOW LEVEL JET REGION OUT AHEAD OF
THE WEAKENING COLORADO MCS. HAVE ADDED POPS ACROSS KANSAS ZONES
DUE TO THE DEVELOPING SHOWERS AND THUNDERSTORMS. BELIEVE THESE
SHOWERS/THUNDERSTORMS WILL REMAIN FAIRLY ISOLATED AND WILL BEGIN
TO DIE OFF BY AROUND OR JUST AFTER SUNRISE AS THE LOW LEVEL JET
GRADUALLY DECREASES. THESE SHOWERS ARE NOT BEING WELL MODELED AND
SO CONFIDENCE IN WHEN THE CONVECTION WILL FINALLY DIE DOWN IS
RATHER MARGINAL.
THERE IS SOME POSSIBILITY OF AFTERNOON SHOWERS AND THUNDERSTORMS
DESPITE OUR CURRENTLY DRY FORECAST. THE 00Z AND 06Z NAM BOTH TRY
TO RE-INITIATE CONVECTION LATE THIS AFTERNOON JUST TO OUR WEST IN
ASSOCIATION WITH THE WEAK SHORT WAVE AS IT TRACKS EAST ACROSS
NEBRASKA. IN ADDITION...SOME WRF MODELS ALSO INDICATE THE
POSSIBILITY OF AFTERNOON CONVECTION ACROSS PORTIONS OF OUR FORECAST
AREA. HOWEVER...EXPECT INCREASING TEMPERATURES WITHIN A CAPPING
INVERSION AS WIND AT 700MB TURNS SOUTHWEST AND WARMER AIR MOVES IN
ALOFT. THE WRF HAS BEEN OVERDOING CONVECTION RECENTLY AND BELIEVE
THAT THE THREAT OF AFTERNOON REDEVELOPMENT IS FAIRLY LOW GIVEN THE
STRENGTHENING CAP. THEREFORE...HAVE ELECTED TO CONTINUE TO CARRY
A DRY FORECAST ACROSS OUR CWA THIS AFTERNOON.
HIGH TEMPERATURES TODAY SHOULD BE WARMER AS OUR WIND WILL BE MORE
SOUTHERLY TODAY AND TEMPERATURES WILL BE WARMING AT MOST ALL
LAYERS OF THE LOWER ATMOSPHERE. HOWEVER...MID TO HIGH
CLOUDS...ESPECIALLY THIS MORNING COULD TAMPER THE WARM UP AND
WILL GO FOR HIGHS RANGING FROM THE UPPER 80S ACROSS NEBRASKA TO
THE 90S ACROSS KANSAS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI AUG 23 2013
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM PERIOD LIES WITH
TEMPERATURES.
MODELS ARE IN GOOD AGREEMENT AT THE START OF THE FORECAST
PERIOD...SHOWING UPPER LEVEL HIGH PRESSURE CENTERED OVER ERN OK/KS
INTO MISSOURI...WITH AN AREA OF LOW PRESSURE SPINNING JUST OFF THE
PAC NW COAST AND TROUGH AXIS EXTENDING SOUTH OFF THE WEST COAST.
THE WEAK WAVE PASSING THROUGH THE FLOW STILL LOOKS TO REMAIN FAR
ENOUGH NORTH NOT TO HAVE AN IMPACT ON THE CWA. THROUGH THE REST OF
THE WEEKEND AND RIGHT ON INTO THE WORK WEEK...GOOD AGREEMENT
CONTINUES BETWEEN MODELS WITH THE OVERALL PATTERN...AND THE DRY
FORECAST REMAINS. THE UPPER LEVEL RIDGE...ESP DURING THE WORK
WEEK...WILL ACTUALLY SLIDE A TOUCH TO THE WEST AS AN UPPER LEVEL
DISTURBANCE/TROUGHING DIGS A BIT FURTHER SOUTH TOWARD THE EAST
COAST. THIS LOOKS TO PLACE THE UPPER LEVEL HIGH MORE SQUARELY OVER
THE AREA...CENTERED OVER KS/PERHAPS NEAR THE KS/NE STATE LINE. ANY
DISTURBANCES WOULD SLIDE NORTH OF THE CWA...WITH THE ATMOSPHERE WELL
CAPPED.
AT THE SURFACE...THE GENERAL PATTERN WILL RESULT IN SOUTHERLY WINDS
THROUGH THE ENTIRE FORECAST PERIOD...AS A TROUGH LIES OVER THE HIGH
PLAINS WITH WEAK HIGH PRESSURE OFF TO THE EAST. THE WEEKEND LOOKS
TO BE BREEZY...ESP SATURDAY...WITH A TIGHTER PRESSURE GRADIENT
EXPECTED TO DEVELOP...POTENTIALLY BRINGING SUSTAINED SPEEDS IN THE
20 TO 25 MPH RANGE WITH HIGHER GUSTS.
AS FAR AS TEMPERATURES GO...WITH MODELS SHOWING 850MB TEMPS
INCREASING INTO THE MID/UPPER 20C RANGE...HIGH TEMPERATURES CWA-WIDE
IN THE 90S DONT LOOK TO BE GOING AWAY ANY TIME SOON. ALSO CANT
COMPLETELY RULE OUT SOME READINGS NEAR THE 100 DEGREE MARK...ESP IN
SWRN LOCATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 516 AM CDT FRI AUG 23 2013
THE MAIN THING TO WATCH OUT FOR TODAY WILL BE THE
DEVELOPING SHOWERS AND ISOLATED THUNDERSTORMS. LATEST 06Z GFS AND
MOST RECENT HRRR MODEL RUN ARE BOTH MORE AGGRESSIVE WITH
GETTING PRECIPITATION TODAY. WILL CONTINUE TO LEAVE THUNDER AND
PRECIPITATION OUT OF THE TAF FOR NOW...BUT THE TAF MAY NEED TO BE
AMENDED DEPENDING ON RADAR TRENDS AND WHERE THESE ISOLATED
THUNDERSTORMS DEVELOP. THE WIND WILL REMAIN OUT OF THE SOUTHEAST
TODAY AND THEN BECOME MORE SOUTHERLY LATE TONIGHT. EXPECT A
SCATTERED TO BROKEN MID DECK OF CLOUDS THROUGH THE MORNING AND
POSSIBLY THROUGH MUCH OF THE DAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...ADO
AVIATION...WESELY
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1118 PM MDT THU AUG 22 2013
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS TO PERSIST THROUGH THE TAF PERIOD OUTSIDE OF
ISOLATED SHOWERS AND THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE
FORECAST AREA FRIDAY AFTERNOON AND EVENING. TERMINALS MOST LIKELY
TO BE IMPACTED ARE KGUP AND KFMN LATE FRIDAY. BRIEF MVFR
CONDITIONS LIKELY WITH THUNDERSTORMS FRIDAY AFTERNOON/EVENING.
11
&&
.PREV DISCUSSION...254 PM MDT THU AUG 22 2013...
NOT MUCH CHANGE TO THE FORECAST. AS EXPECTED...EVEN LESS CONVECTION
HAS POPPED UP THIS AFTERNOON AS THE DRY WEDGE AHEAD OF THE EASTERLY
WAVE MOVES ACROSS THE STATE. ALSO OF NOTE IS A PRETTY HEALTHY
INVERSION AROUND 550 MB ON THE 12Z ABQ SOUNDING. BEST CHANCES FOR
STORMS FOR THE REST OF THE EVENING WILL BE ACROSS THE NORTHERN
MTNS...AND IF THE HRRR IS CORRECT...MOST OF THE PRECIPITATION WILL
BE DONE BY 03Z.
THE DRY WEDGE SHOULD BE OVER NORTHERN NM TOMORROW. MEANWHILE...THE
UPPER HIGH WILL CONTINUE TO CREEP EASTWARD...AND WILL BE CENTERED
OVER OK/KS BY TOMORROW AFTN. THIS WILL ALLOW SOME OF THE MOISTURE
ASSOCIATED WITH THE EASTERLY WAVE TO CREEP UP INTO NM FRIDAY
AFTN/NIGHT. THIS SHOULD ALLOW FOR AN UPTICK IN SHOWER AND
THUNDERSTORM COVERAGE ON SATURDAY...MAINLY ACROSS THE HIGHER
TERRAIN.
BY SUNDAY AFTN...THE UPPER HIGH STRENGTHENS TO 596DAM AND THE
WESTWARD EXTENSION OF THE HIGH WILL BUILD BACK INTO NM. THIS WILL
KEEP THE BULK OF THE MOISTURE ASSOCIATED WITH AND AHEAD OF NOW
TROPICAL DEPRESSION NINE-E TO THE WEST OF THE STATE. INSTEAD...IT
APPEARS SOME RELATIVELY DRIER AIR WILL CIRCLE IN OVER NM.
THE GFS WANTS TO BRING ANOTHER WEAK WAVE ROUNDING THE SOUTH SIDE OF
THE UPPER HIGH INTO THE STATE ON MONDAY. THERE IS SOME MODEST
MOISTURE ASSOCIATED WITH THIS... SO THERE MAY BE A FEW MORE STORMS
THAN ON SUNDAY. HOWEVER THE ECMWF DOES NOT REALLY SHOW THIS FEATURE
OR THE MOISTURE MOVING UP INTO NM UNTIL AT LEAST 24 HOURS LATER. SO
FOR NOW...MONDAY-WEDNESDAY LOOKS FAIRLY MINIMAL PRECIPITATION-WISE.
LATER IN THE WEEK...MODELS LOOK TO WEAKEN THE WESTWARD EXTENSION OF
THE HIGH...WHICH MAY ALLOW FOR SOME RICHER MONSOON MOISTURE TO MOVE
INTO WESTERN AND CENTRAL NM...ESPECIALLY IF THERE IS INDEED A SECOND
TROPICAL SYSTEM LURKING SOUTH OF THE BAJA AS MODELS ARE INDICATED.
34
.FIRE WEATHER...
A MORE STABLE AND DRIER AIRMASS HAS INFILTRATED A LARGE PORTION OF
THE FORECAST AREA TODAY. THE RESULT IS ISOLATED SMALLER FOOTPRINTS
OF WETTING RAIN. THE STEERING FLOW FOR THE STORMS THE REST OF TODAY
WILL BE TOWARDS THE NORTHEAST.
THE HEART OF THE DRIER AIRMASS WILL SHIFT TO THE NORTH AND NORTHEAST
ON FRIDAY. THUNDERSTORM COVERAGE WILL INCREASE BUT THE WETTING RAIN
FOOTPRINT WONT INCREASE TOO MUCH. HIGH TEMPERATURES WILL BE NEAR TO
SLIGHTLY BELOW NORMAL SOUTH AND NEAR TO SLIGHTLY ABOVE NORMAL NORTH.
VENTILATION RATES WILL BE PRETTY GOOD AS SOUTH/SOUTHEAST WINDS
INCREASE ACROSS THE AREA. SOME BREEZES WILL BE OBSERVED ACROSS THE
EASTERN PLAINS...ESPECIALLY NORTHEAST WHERE A LEE SURFACE TROUGH
STRENGTHENS.
THE UPPER HIGH WILL STRENGTHEN AND BECOME DOMINATE OVER THE SOUTHERN
PLAINS AND MID MISSISSIPPI VALLEY REGION DURING THE WEEKEND.
CONFIDENCE IS PRETTY HIGH FOR THAT PATTERN. DUE TO THE ABOVE NORMAL
STRENGTH TO THE UPPER HIGH...THUNDERSTORM COVERAGES WILL VARY.
SATURDAY STILL LOOKS TO BE A MORE ACTIVE WETTING THUNDERSTORM DAY.
THE CONTINENTAL DIVIDE AND TO A LESSER EXTENT THE CENTRAL MTN CHAIN
WOULD BE FAVORED. THERE IS SOME DISCREPANCY IN THE MODELS AS FAR AS
CENTRAL MOUNTAINS ARE CONCERNED. STEERING FLOW ON SATURDAY WOULD
TAKE THE STORMS TOWARDS THE NORTH AND NORTHEAST. A DRIER AND MORE
STABLE AIRMASS PIVOTING AROUND THE UPPER HIGH IS STILL EXPECTED TO
INVADE PORTIONS OF THE AREA ON SUNDAY. THE ECMWF/GFS AND NAM
MODELS DEPICT THIS. BREEZES WOULD ENHANCE ACROSS THE EASTERN
PLAINS DURING THE WEEKEND. THIS IS A RESULT OF AN UNUSUALLY STRONG
LEE SIDE SURFACE TROUGH THAT IS EXPECTED TO STRENGTHEN DURING THE
PERIOD. THE PEAK WIND PERIOD WOULD BE ON SATURDAY.
THE LONGER RANGE MODELS STILL SHOW THE MAIN MONSOONAL PLUME WRAPPING
AROUND THE UPPER HIGH OVER ARIZONA AND FAR WEST NEW MEXICO DURING
THE EARLIER HALF OF NEXT WEEK. THE DRIER AND MORE STABLE AIRMASS
WOULD GET SHIFTED SOME TOWARDS THE EAST SO THUNDERSTORM COVERAGE
EACH DAY SHOULD INCREASE SLIGHTLY FROM WEST TO EAST. AGAIN...MAINLY
KEEPING STORMS WEST OF THE CENTRAL MTNS AND ESPECIALLY FAVORING THE
CONTINENTAL DIVIDE. TEMPERATURES WOULD BE ABOVE NORMAL EAST AND NEAR
NORMAL WEST. THE LEE TROUGH WILL REMAIN ACROSS THE EASTERN PLAINS
BUT IS EXPECTED TO WEAKEN SOME AS TIME PROGRESSES. THUS LOOK FOR THE
OVERALL WIND FLOW TO LESSEN SOME. GUSTY OUTFLOW WINDS WOULD REMAIN A
CONCERN HOWEVER...ACROSS WESTERN AND CENTRAL AREAS.
THE ECMWF AND GFS REMAINS PRETTY STEADFAST IN KEEPING THE MAIN UPPER
HIGH CENTER TO THE EAST OF THE STATE THE LATTER HALF OF NEXT WEEK.
THE HIGH ALSO LOOKS TO BE QUITE STRONG AND SIMILAR TO THE STRENGTH
AND POSITION IT WAS AUGUST 2011. MOISTURE WOULD CONTINUE TO OOZE
EASTWARD DUE TO OUTFLOW BOUNDARIES FROM CONVECTION ACROSS THE WEST
BUT THE FAVORED AREAS FOR WETTING RAIN WOULD REMAIN WEST. THE
EASTERN PLAINS ONCE AGAIN LOOK TO BE ON THE DRIER AND WARMER SIDE.
THE CURING OF NEW GRASS GROWTH ACROSS THE EAST WOULD MOST LIKELY
START UP DURING THIS PERIOD.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
52
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
329 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA LATE TONIGHT INTO SATURDAY MORNING
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS. THIS FRONT WILL PUSH
SOUTH OF THE AREA DURING SATURDAY...AS HIGH PRESSURE BUILDS DOWN
FROM THE NORTH. COOLER AND DRIER CONDITIONS WILL DEVELOP SUNDAY
INTO NEXT WEEK. A WARMING TREND WILL TAKE PLACE BY THE MIDDLE OF
NEXT WEEK AS HIGH PRESSURE SHIFTS OFFSHORE.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 130 PM FRIDAY...CONVECTION HAS STARTED TO DEVELOP IN THE PAST
HALF HOUR. AS MENTIONED EARLIER THE MORE ORGANIZED CONVECTION IS
EXPECTED AFTER 21 UTC WITH THE APPROACHING SHORT WAVE LOCATED IN
NORTHWEST VIRGINIA. THE NAM AND 15 UTC RUC MOVE THIS FEATURE
TOWARDS THE AREA JUST AFTER 20 UTC. SO EXPECT TO SEE UNORGANIZED
CONVECTION WITH A FEW BOUNDARY INTERACTIONS BEFORE 20 UTC. THEN AS
THE HIGH RESOLUTION MODELS ARE SHOWING...A LINE OR LINE SEGMENTS
OF CONVECTION...WILL DEVELOP OR ADVECT FROM THE THE NORTHWEST AND
INTO THE REGION.
TIMING OF THE FRONTAL PASSAGE APPEARS TO BE ALONG A LINE FROM
LUMBERTON TO BURGAW BY 06 UTC AND THE FRONT SHIFTS TO A LINE NEAR
A MYRTLE BEACH TO KINGSTREE LINE. WITH THIS FRONTAL PASSAGE LOW
TEMPERATURES ARE EXPECTED TO REACH THE UPPER 60S IN THE NORTH AND
THE LOWER 70S IN THE SOUTH.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...COLD FRONT WILL CROSS THE AREA AND BE JUST
SOUTH OF THE CWA AT THE START OF THE PERIOD. THIS LEAVES NE FLOW
ACROSS THE CWA AS HIGH PRESSURE RIDGES DOWN THE COAST...BECOMING
ALIGNED JUST WEST OF THE CWA THROUGH THE WKND. WHILE SATURDAY WILL
SHOW SLOW IMPROVEMENTS...LOW LEVEL MOISTURE WILL BE TOUGH TO
ERODE...ESPECIALLY NEAR THE COAST. THIS IS ECHOED IN FORECAST
PROFILES AND EVIDENT BY WEAK CONTINUATION OF 850-925MB THETA-E RIDGE
THROUGH SAT NIGHT. SCHC/ISOLATED SHOWERS WILL BE POSSIBLE THE FIRST
HALF OF SATURDAY BEHIND THE FRONT...BUT CLEARING/DRYING WILL OCCUR
LATE IN THE DAY...AND PWATS DROP TO ONE INCH OR LESS (PRETTY
INCREDIBLE FOR AUGUST) BY SUNDAY MORNING. DRY HIGH PRESSURE ENVELOPS
THE AREA SUNDAY...AND A BEAUTIFUL LATE-SUMMER DAY ON TAP WITH AMPLE
SUNSHINE AND WARM BUT BELOW NORMAL TEMPS.
HIGHS THROUGH THE WKND WILL BE ONLY IN THE LOW/MID 80S...COOLER
SUNDAY...WITH LOWS FALLING INTO THE LOW 60S...WITH POSSIBLY A FEW
58S AND 59S SUNDAY NIGHT IN THE COLD SPOTS THANKS TO THIS INCREDIBLY
DRY AIR MASS!
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...LARGE UPPER LEVEL RIDGE OVER THE CENTER OF THE
NATION ON MONDAY. A SLIGHT RETROGRESSION OF THIS FEATURE WILL ALLOW
FOR A NW FLOW TO DEVELOP LOCALLY BY MID WEEK...ONLY TO BE
STRENGTHENED THURSDAY AND FRIDAY AS AN UPPER TROUGH FORMS OFF THE
NEW ENGLAND COAST. SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTH
WILL KEEP TEMPS A LITTLE BELOW CLIMO UNTIL AROUND WEDNESDAY WHEN
THE CENTER OF THE WEAKENING HIGH DRIFTS TO OUR SOUTH AND A PIEDMONT
TROUGH DEVELOPS. THE LATE PERIOD SHARPENING OF THE UPPER TROUGH
DRIVES A COOL FRONT THROUGH ON THURSDAY. MODELS SHOWING A FAIR
AMOUNT OF PRECIP WITH ITS PASSAGE BUT GIVEN THE NEARLY NONEXISTENT
MOISTURE FLUX AHEAD OF IT PREFER TO KEEP POPS AT SLIGHT CHANCE.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...A COLD FRONT WILL DROP SOUTHEAST THIS AFTERNOON...WITH
MODERATE CONFIDENCE FOR A BAND OF CONVECTION ON THE LEADING EDGE.
MODERATE CONVERGENCE AND MODERATE TO STRONG CAPE SHOULD PRODUCE
THUNDERSTORMS WITH GUSTY WINDS AS THEY DROP SOUTHEAST AROUND 20
MPH. SMALL HAIL COULD ALSO OCCUR...GIVEN THE NORTHWEST FLOW.
TIMING MAY BE A BIT FAST AT THIS TIME...BUT FEEL THIS COULD BE
MORE SQUALLY IN NATURE...AND THEY TEND TO OUTRUN THEIR SUPPORT.
THERE WILL PROBABLY BE SEVERAL HOURS OF LIGHT SHOWERS BEHIND THE
FRONT. WINDS WILL SHIFT FROM SOUTHWEST TO WEST NORTHWEST AS THE
STORMS MOVE IN. CEILINGS WILL BE VFR FOR THE MOST PART...WITH SOME
BRIEF IFR VISIBILITIES IN THE HEAVIER CONVECTION. OVERNIGHT...WINDS
WILL CONTINUE TO VEER TO THE NORTHWEST AS THE RAIN SLOWLY ENDS
AFTER 05Z. A POST FRONTAL VFR STRATA CU CEILING IS EXPECTED.
SATURDAY...VFR WITH A CONTINUED STRATA CU CEILING AND LIGHT NORTHERLY
WINDS.
EXTENDED OUTLOOK...VFR SATURDAY AFTERNOON THROUGH MONDAY. SCATTERED
CONVECTION TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...WEST TO SOUTHWESTERLY WINDS OF 10 TO 15 KNOTS
ARE BLOWING OVER THE WATERS THIS AFTERNOON. AS A FRONTAL BOUNDARY
NEARING THE VIRGINIA AND NORTH CAROLINA BORDER SHIFTS SOUTHWARD
WINDS WILL BECOME MORE SOUTHWESTERLY THROUGH THE EVENING. THE
WIND SHIFT WITH THE FRONT IS EXPECTED TO BEGIN JUST AFTER 06 UTC
NEAR SURF CITY AND AFTER 12 UTC BY THE LOWER SANTEE RIVER. SEAS
ARE EXPECTED TO REMAIN IN THE 2 TO 3 FOOT RANGE THROUGH SATURDAY
MORNING.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...COLD FRONT SOUTH OF THE AREA AT THE START OF
THE PERIOD WILL PUSH FURTHER SOUTH THROUGH THE DAY IN RESPONSE TO A
HIGH PRESSURE BUILDING SOUTH FROM NEW ENGLAND. HIGH PRESSURE AXIS
REMAINS WEST OF THE LOCAL AREA...SO WATERS BECOME ALIGNED WITHIN A
PINCHED GRADIENT AND A NE SURGE DEVELOPS LATE SATURDAY AND MUCH OF
SUNDAY. WINDS INCREASE FROM NORTH AT 10 KTS TO START THE PERIOD...TO
NE UP TO 20 KTS ON SUNDAY...BEFORE FALLING BACK TO NE AT 10-15 KTS
LATE. SEAS BUILD IN RESPONSE TO THE INCREASING WINDS...FROM 2-3 FT
SATURDAY UP TO 3-5 FT SUNDAY...AND A SCEC WILL LIKELY BE NEEDED FOR
THE WATERS THE SECOND HALF OF THE SHORT TERM.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...BROAD SWATH OF NE WINDS ALONG THE SOUTHEAST
COAST ON MONDAY AS HIGH PRESSURE DIVES IN FROM POINTS NORTH. THE
FLOW WILL EASE AS THE DAY WEARS ON AND THE GRADIENT RELAXES. WIND
WILL TURN LIGHT AND VARIABLE MONDAY NIGHT AND THEN A SOUTHERLY
COMPONENT BECOMES PREDOMINANT ON TUESDAY DUE TO FORMATION OF A
PIEDMONT TROUGH. SW FLOW INCREASES ON WEDNESDAY ALLOWING FOR
BUILDING SEAS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DRH
SHORT TERM...JDW
LONG TERM...MBB
AVIATION...DRH
MARINE...JDW/MBB/DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
131 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT APPROACHING FROM THE NORTHWEST THIS EVENING WILL
PUSH SOUTH OF THE AREA BY EARLY SATURDAY. THE COLD FRONT WILL
USHER IN COOLER AND DRIER CONDITIONS FOR THE WEEKEND INTO EARLY
NEXT WEEK. A WARMING TREND WILL TAKE PLACE BY THE MIDDLE OF NEXT
WEEK AS HIGH PRESSURE SHIFTS OFFSHORE AND COLD FRONT APPROACHES
THE CAROLINAS FROM THE NORTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...CONVECTION HAS STARTED TO DEVELOP IN THE PAST
HALF HOUR. AS MENTIONED EARLIER THE MORE ORGANIZED CONVECTION IS
EXPECTED AFTER 21 UTC WITH THE APPROACHING SHORT WAVE LOCATED IN
NORTHWEST VIRGINIA. THE NAM AND 15 UTC RUC MOVE THIS FEATURE
TOWARDS THE AREA JUST AFTER 20 UTC. SO EXPECT TO SEE UNORGANIZED
CONVECTION WITH A FEW BOUNDARY INTERACTIONS BEFORE 20 UTC. THEN AS
THE HIGH RESOLUTION MODELS ARE SHOWING A LINE OR LINE SEGMENTS OF
CONVECTION DEVELOPING OR ADVECT FROM THE THE NORTHWEST AND INTO THE
REGION.
TIMING OF THE FRONTAL PASSAGE APPEARS TO BE ALONG A LINE FROM
LUMBERTON TO BURGAW BY 06 UTC AND THE FRONT SHIFTS TO A LINE NEAR
A MYRTLE BEACH TO KINGSTREE LINE. WITH THIS FRONTAL PASSAGE LOW
TEMPERATURES ARE EXPECTED TO REACH THE UPPER 60S IN THE NORTH AND
THE LOWER 70S IN THE SOUTH.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE H5 TROUGH WILL PUSH FRONT SOUTH BY SAT
MORNING...BUT WILL KEEP POTENTIAL FOR SHWRS ON SAT WITH BEST
CONVERGENCE FROM THE TIP OF CAPE FEAR SOUTH...WHERE BEST
CONVERGENCE AND RESIDUAL MOISTURE WILL BE.
DEEP N-NW FLOW DEVELOPING BEHIND FRONT AS MID TO UPPER TROUGH
AXIS SHIFTS FARTHER OFF THE COAST AND HIGH PRESSURE BUILDS IN
THROUGH SATURDAY. PCP WATER VALUES WILL DROP FROM CLOSE TO 2
INCHES AHEAD OF FRONT TO LESS THAN AN INCH BY END OF PERIOD OR
EARLY SUNDAY. THEREFORE EXPECT CLEARING THROUGH SAT NIGHT FROM
NORTH TO SOUTH. RESIDUAL LOW LEVEL MOISTURE FROM PCP MAY PRODUCE FOG
ACROSS THE AREA SAT NIGHT.
HIGHS SATURDAY WILL REACH INTO THE LOW 80S AFTER A FAIRLY WARM
START DUE TO CLOUDS AND SHOWERS ASSOCIATED WITH THE COLD FRONT.
LOWS SATURDAY NIGHT WILL FALL DOWN INTO THE 60S AS A MUCH DRIER
AIRMASS MOVES INTO THE REGION. SUNDAY WILL RUN BELOW NORMAL AS
RELATIVELY COOLER AND DRIER AIR MASS BUILDS DOWN OVER AREA.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...RIDGE PUSHES IN FROM THE WEST THROUGH THE
MID TO UPPER LEVELS WHILE HIGH PRESSURE NOSES DOWN FROM THE NORTH
MONDAY AS IT SHIFTS EAST OFF THE MID ATLANTIC COAST THROUGH
TUESDAY. THE RIDGE RETREATS WESTWARD THROUGH MID WEEK AS
SHORTWAVES RIDE AROUND IT REACHING INTO THE SOUTHEAST ON
WEDNESDAY AS IT PUSHES A COLD FRONT SOUTHEAST. THIS MAY PRODUCE
INCREASED CLOUDS AND CHC OF SHWRS ON WED BEFORE HIGH PRESSURE
BUILDS IN BEHIND IT BY LATE THURS INTO FRI.
OVERALL EXPECT PLENTY OF SUNSHINE WITH TEMPS MODERATING FROM
BELOW NORMAL MONDAY TO ABOVE NORMAL BY WED AS MID TO UPPER RIDGE
BUILDS EAST INTO THE CAROLINAS PRODUCING H5 HEIGHT RISES. GRADIENT
WINDS WILL WEAKEN AS HIGH SHIFTS SOUTH AND EAST WITH MAINLY
DIURNAL SHIFTS DUE TO SEA BREEZE/LAND BREEZE. 850 TEMPS WILL
BOTTOM OUT AROUND 13C IN COOLER AIR ADVECTING IN BEHIND FRONT
AND WILL RISE UP TO 18C BY TUES INTO WED. THE DIURNAL SWINGS IN
TEMPS WILL BE FAIRLY LARGE WITH DRY AIR IN PLACE AND DEWPOINT
TEMPS REACHING DOWN INTO THE 50S OVER NORTHERN TIER ZONES MONDAY
AND TUES. AS HIGH PRESSURE SHIFTS OFF SHORE AND COLD FRONT MAKES
ITS WAY SOUTHEAST BY WED EXPECT WARMER SOUTHERLY FLOW BRINGING
TEMPS BACK UP TOWARD NORMAL WITH READINGS IN THE MID 80S AND
AROUND 90 BY THURS.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 18Z...A COLD FRONT WILL DROP SOUTHEAST THIS AFTERNOON...WITH
MODERATE CONFIDENCE FOR A BAND OF CONVECTION ON THE LEADING EDGE.
MODERATE CONVERGENCE AND MODERATE TO STRONG CAPE SHOULD PRODUCE
THUNDERSTORMS WITH GUSTY WINDS AS THEY DROP SOUTHEAST AROUND 20
MPH. SMALL HAIL COULD ALSO OCCUR...GIVEN THE NORTHWEST FLOW.
TIMING MAY BE A BIT FAST AT THIS TIME...BUT FEEL THIS COULD BE
MORE SQUALLY IN NATURE...AND THEY TEND TO OUTRUN THEIR SUPPORT.
THERE WILL PROBABLY BE SEVERAL HOURS OF LIGHT SHOWERS BEHIND THE
FRONT. WINDS WILL SHIFT FROM SOUTHWEST TO WEST NORTHWEST AS THE
STORMS MOVE IN. CEILINGS WILL BE VFR FOR THE MOST PART...WITH SOME
BRIEF IFR VISIBILITIES IN THE HEAVIER CONVECTION. OVERNIGHT...WINDS
WILL CONTINUE TO VEER TO THE NORTHWEST AS THE RAIN SLOWLY ENDS
AFTER 05Z. A POST FRONTAL VFR STRATA CU CEILING IS EXPECTED.
SATURDAY...VFR WITH A CONTINUED STRATA CU CEILING AND LIGHT NORTHERLY
WINDS.
EXTENDED OUTLOOK...VFR SATURDAY AFTERNOON THROUGH MONDAY. SCATTERED
CONVECTION TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...WEST TO SOUTHWESTERLY WINDS OF 10 TO 15 KNOTS
ARE BLOWING OVER THE WATERS THIS AFTERNOON. AS A FRONTAL BOUNDARY
NEARING THE VIRGINIA AND NORTH CAROLINA BORDER SHIFTS SOUTHWARD
WINDS WILL BECOME MORE SOUTHWESTERLY THROUGH THE EVENING. THE
WIND SHIFT WITH THE FRONT IS EXPECTED TO BEGIN JUST AFTER 06 UTC
NEAR SURF CITY AND AFTER 12 UTC BY THE LOWER SANTEE RIVER. SEAS
ARE EXPECTED TO REMAIN IN THE 2 TO 3 FOOT RANGE THROUGH SATURDAY
MORNING.
SHORT TERM /SATURDAY THROUGH SUNDAY
NIGHT/... AS OF 3 AM FRIDAY...WINDS WILL SHIFT RAPIDLY TO THE
NORTH SATURDAY MORNING BEHIND COLD FRONT. WINDS MAY INCREASE UP TO
A SOLID 15 KTS OR POSSIBLY UP TO 20 KTS OVERNIGHT SATURDAY INTO
SUNDAY IN NORTHEAST SURGE BEHIND FRONT. SEAS WILL INCREASE IN
NORTHEAST SURGE BEHIND FRONT THROUGH SATURDAY NIGHT INTO THE
LATTER HALF OF THE WEEKEND...FROM 2 TO 3 FT WITH 2 TO 4 FT RANGE
LATE SATURDAY AND MAYBE SLIGHTLY HIGHER AS CAA INCREASES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...THE WINDS WILL LIGHTEN AS HIGH PRESSURE SHIFTS
SOUTH AND WEAKENS AND AIR MASS BEGINS TO MODIFY THROUGH LATE
MONDAY. OVERALL SEAS WILL BE 2 TO 4 FT MOST WATERS. A FURTHER
SHIFTING OF THE HIGH TO BASICALLY OVERHEAD WILL LEAD TO WINDS
BASICALLY LIGHT AND VARIABLE TUESDAY. OVERALL SEAS WILL TREND DOWN
TO AROUND TWO FEET TUESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
252 AM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH THIS AFTERNOON...THEN PUSH
SOUTH THROUGH THE REGION TONIGHT AS AN UPPER LEVEL TROUGH DIGS
SOUTHEAST ACROSS THE MID ATLANTIC. COOL AND DRY HIGH PRESSURE WILL
BUILD INTO THE CAROLINAS FROM THE NORTH IN THE WAKE OF THE COLD
FRONT ON SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 945 PM THURSDAY...
SEVERAL CLUSTERS OF PROBLEMATIC STORMS HAVE AFFECTED MAINLY THE
EASTERN CWA SINCE LATE AFTERNOON... BUT ISOLATED STORM CLUSTERS
PERSIST AROUND THE ENTIRE AREA AS A MODERATELY UNSTABLE AIR MASS
(MLCAPE VALUES STILL 1500-2000 J/KG) LINGERS. DEEP LAYER SHEAR
REMAINS RESPECTABLE AT 25-30 KTS IN THE BASE OF THE MID LEVEL
SHORTWAVE TROUGH NOW SWINGING THROUGH NY/DE/ERN VA/ERN NC... BUT
THIS SHOULD BE WANING OVERNIGHT AS THE TROUGH PROGRESSES OFFSHORE.
INSTABILITY IS LIKEWISE EXPECTED TO FALL BELOW 1000 J/KG
OVERNIGHT... AND WITH PRECIP WATER VALUES HAVING DROPPED TO AT OR
UNDER 1.5 INCHES OVER MUCH OF CENTRAL NC ACCORDING TO BLENDED TPW
IMAGERY... WE SHOULD SEE EVEN THE ISOLATED STORM CLUSTERS LESSEN IN
COVERAGE AND INTENSITY OVER THE NEXT SEVERAL HOURS AS WE LOSE BOTH
DYNAMIC AND THERMODYNAMIC SUPPORT. WILL RETAIN THE ISOLATED STORM
MENTION FOR ANOTHER FEW HOURS BEFORE DROPPING SHOWER/STORM CHANCES
TO UNDER 15 PERCENT LATE TONIGHT. THIS FOLLOWS RECENT HRRR MODEL
OUTPUT TRENDS. FAIR TO PARTLY CLOUDY SKIES AND LIGHT WINDS WILL
FACILITATE PATCHY FOG DEVELOPMENT LATE. LOW 68-72... IN LINE WITH
STATISTICAL GUIDANCE AND PERSISTENCE. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 239 AM FRIDAY...
MUCH DRIER AND COOLER AIR WILL OVERSPREAD THE REGION THIS WEEKEND
COURTESY OF THE MODERATELY STRONG SURFACE HIGH PRESSURE (1026+ MB)
THAT WILL BUILD FROM NEW ENGLAND DOWN THE ATLANTIC SEABOARD INTO
SC/GA THROUGH SUNDAY NIGHT. THE ONLY ISSUE REALLY WILL BE THE AMOUNT
OF CLOUDINESS THAT WILL AFFECT OUR REGION SATURDAY. MODELS AGREE IN
PUSHING THE COLD FRONT WELL THROUGH THE REGION BY 12Z/SAT. DAA/CAA
WILL OCCUR WITH THE NE FLOW AT THE SURFACE. HOWEVER... SOME MODEL
SOLUTIONS INDICATE A TEMPERATURE INVERSION WITH MOISTURE BECOMING
TRAPPED UNDER THAT INVERSION IMMEDIATELY BEHIND THE FRONT SATURDAY
MORNING INTO THE EARLY AFTERNOON. ALTHOUGH MEASURABLE RAIN IS NOT
EXPECTED... VARIABLY CLOUDY SKIES SHOULD RESULT ESPECIALLY IN THE
SOUTH AND WEST THROUGH SATURDAY AFTERNOON. EXPECT DECREASING
CLOUDINESS FROM N TO S SAT AFTERNOON INTO SAT NIGHT. MOSTLY SUNNY
SKIES SUNDAY. HIGHS 80-85 BOTH DAYS. LOWS 55-63 SUNDAY AND MONDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 239 AM FRIDAY...
THE BUILDING UPPER RIDGE OVER THE MID-MISSISSIPPI VALLEY NEXT WEEK
POSES A BIT OF A PROBLEM FOR OUR REGION... THE RETURN OF THE NW FLOW
ALOFT. THIS SHOULD BE MOST PRONOUNCED TUESDAY AND BEYOND WHEN
SEVERAL VORTICITY MAXIMUMS IN THE NW FLOW (WHICH WILL BE HARD TO
TIME) MAY AFFECT OUR REGION. EXPECT INCREASING HEAT... HUMIDITY...
AND THE CHANCE OF THUNDERSTORMS MID TO LATE WEEK. STILL... NO HEAT
WAVE CONDITIONS ARE ANTICIPATED ALONG OR EAST OF THE APPALACHIANS
WITH THIS PATTERN. MONDAY... MOSTLY SUNNY. LOWS 55-62. HIGHS 80-85.
TUESDAY AND WEDNESDAY... PARTLY SUNNY. A SLIGHT CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS IN THE NW TUESDAY... THEN A CHANCE ALL
ZONES WEDNESDAY AND THURSDAY. LOWS MODERATING INTO THE LOWER 70S BY
THURSDAY. HIGHS 85-90.
&&
.AVIATION /06Z FRIDAY THROUGH WEDNESDAY/...
AS OF 230 AM FRIDAY...
24-HR TAF PERIOD:
ANTICIPATE A CHANCE FOR MVFR FOG AT ALL TAF SITES BETWEEN 08-11Z
THIS MORNING. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL THROUGH
EARLY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE ANTICIPATED
TO DEVELOP BY EARLY/MID AFTERNOON IN ADVANCE OF AN UPPER LEVEL
DISTURBANCE AND ASSOCIATED COLD FRONT APPROACHING THE REGION FROM
THE NORTHWEST...WITH SCATTERED CONVECTION TRACKING SOUTHEAST ACROSS
CENTRAL NC DURING THE MID/LATE AFTERNOON (18-00Z) HOURS. ALL TAF
SITES WILL LIKELY BE AFFECTED BY CONVECTION...THOUGH THE TERMINALS
WITH THE BEST OVERALL CHANCE FOR SHOWERS/STORMS (AND BEST CHANCE FOR
AN ISOLD SEVERE STORM) WILL BE RDU/RWI/FAY. WINDS WILL VEER FROM
W/NW TO NORTHEAST AT 5-10 KT IN THE WAKE OF THE FRONT BETWEEN SUNSET
AND MIDNIGHT...OR THE 00-04Z TIME FRAME. A BRIEF PERIOD OF MVFR/IFR
CEILINGS CANNOT BE RULED OUT OVERNIGHT BETWEEN 04-12Z SAT AS
LOW-LEVEL FLOW INITIALLY STRENGTHENS OUT OF THE NORTHEAST...THOUGH
PROBABILITIES ARE TOO LOW TO MENTION AND ANY SUB-VFR CEILINGS WOULD
BE SHORT-LIVED AS A MUCH DRIER AIRMASS ADVECTS INTO CENTRAL NC BY OR
SHORTLY AFTER SUNRISE SAT.
LOOKING AHEAD:
EXCELLENT (VFR) AVIATION CONDITIONS WILL PREVAIL SAT-MON IN ASSOC/W
DRY HIGH PRESSURE EXTENDING INTO AND EVENTUALLY SETTLING OVER THE
CAROLINAS FROM THE NORTH. A BRIEF PERIOD OF SUB-VFR FOG CANNOT BE
RULED OUT AROUND SUNRISE MONDAY MORNING. ANTICIPATE AN INCREASING
CHANCE FOR PRIMARILY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
TUE-THU. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
239 AM EDT FRI AUG 23 2013
.SYNOPSIS...
A PRE-FRONTAL TROUGH WILL LINGER OVER THE REGION TODAY. A COLD FRONT
WILL PUSH SOUTH THROUGH NORTH CAROLINA FRIDAY NIGHT AND EARLY
SATURDAY. HIGH PRESSURE WILL BRING COOLER AND DRIER AIR FOR THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 945 PM THURSDAY...
SEVERAL CLUSTERS OF PROBLEMATIC STORMS HAVE AFFECTED MAINLY THE
EASTERN CWA SINCE LATE AFTERNOON... BUT ISOLATED STORM CLUSTERS
PERSIST AROUND THE ENTIRE AREA AS A MODERATELY UNSTABLE AIR MASS
(MLCAPE VALUES STILL 1500-2000 J/KG) LINGERS. DEEP LAYER SHEAR
REMAINS RESPECTABLE AT 25-30 KTS IN THE BASE OF THE MID LEVEL
SHORTWAVE TROUGH NOW SWINGING THROUGH NY/DE/ERN VA/ERN NC... BUT
THIS SHOULD BE WANING OVERNIGHT AS THE TROUGH PROGRESSES OFFSHORE.
INSTABILITY IS LIKEWISE EXPECTED TO FALL BELOW 1000 J/KG
OVERNIGHT... AND WITH PRECIP WATER VALUES HAVING DROPPED TO AT OR
UNDER 1.5 INCHES OVER MUCH OF CENTRAL NC ACCORDING TO BLENDED TPW
IMAGERY... WE SHOULD SEE EVEN THE ISOLATED STORM CLUSTERS LESSEN IN
COVERAGE AND INTENSITY OVER THE NEXT SEVERAL HOURS AS WE LOSE BOTH
DYNAMIC AND THERMODYNAMIC SUPPORT. WILL RETAIN THE ISOLATED STORM
MENTION FOR ANOTHER FEW HOURS BEFORE DROPPING SHOWER/STORM CHANCES
TO UNDER 15 PERCENT LATE TONIGHT. THIS FOLLOWS RECENT HRRR MODEL
OUTPUT TRENDS. FAIR TO PARTLY CLOUDY SKIES AND LIGHT WINDS WILL
FACILITATE PATCHY FOG DEVELOPMENT LATE. LOW 68-72... IN LINE WITH
STATISTICAL GUIDANCE AND PERSISTENCE. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 239 AM FRIDAY...
MUCH DRIER AND COOLER AIR WILL OVERSPREAD THE REGION THIS WEEKEND
COURTESY OF THE MODERATELY STRONG SURFACE HIGH PRESSURE (1026+ MB)
THAT WILL BUILD FROM NEW ENGLAND DOWN THE ATLANTIC SEABOARD INTO
SC/GA THROUGH SUNDAY NIGHT. THE ONLY ISSUE REALLY WILL BE THE AMOUNT
OF CLOUDINESS THAT WILL AFFECT OUR REGION SATURDAY. MODELS AGREE IN
PUSHING THE COLD FRONT WELL THROUGH THE REGION BY 12Z/SAT. DAA/CAA
WILL OCCUR WITH THE NE FLOW AT THE SURFACE. HOWEVER... SOME MODEL
SOLUTIONS INDICATE A TEMPERATURE INVERSION WITH MOISTURE BECOMING
TRAPPED UNDER THAT INVERSION IMMEDIATELY BEHIND THE FRONT SATURDAY
MORNING INTO THE EARLY AFTERNOON. ALTHOUGH MEASURABLE RAIN IS NOT
EXPECTED... VARIABLY CLOUDY SKIES SHOULD RESULT ESPECIALLY IN THE
SOUTH AND WEST THROUGH SATURDAY AFTERNOON. EXPECT DECREASING
CLOUDINESS FROM N TO S SAT AFTERNOON INTO SAT NIGHT. MOSTLY SUNNY
SKIES SUNDAY. HIGHS 80-85 BOTH DAYS. LOWS 55-63 SUNDAY AND MONDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 239 AM FRIDAY...
THE BUILDING UPPER RIDGE OVER THE MID-MISSISSIPPI VALLEY NEXT WEEK
POSES A BIT OF A PROBLEM FOR OUR REGION... THE RETURN OF THE NW FLOW
ALOFT. THIS SHOULD BE MOST PRONOUNCED TUESDAY AND BEYOND WHEN
SEVERAL VORTICITY MAXIMUMS IN THE NW FLOW (WHICH WILL BE HARD TO
TIME) MAY AFFECT OUR REGION. EXPECT INCREASING HEAT... HUMIDITY...
AND THE CHANCE OF THUNDERSTORMS MID TO LATE WEEK. STILL... NO HEAT
WAVE CONDITIONS ARE ANTICIPATED ALONG OR EAST OF THE APPALACHIANS
WITH THIS PATTERN. MONDAY... MOSTLY SUNNY. LOWS 55-62. HIGHS 80-85.
TUESDAY AND WEDNESDAY... PARTLY SUNNY. A SLIGHT CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS IN THE NW TUESDAY... THEN A CHANCE ALL
ZONES WEDNESDAY AND THURSDAY. LOWS MODERATING INTO THE LOWER 70S BY
THURSDAY. HIGHS 85-90.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 730 PM THURSDAY...
A SURFACE TROUGH...AS WELL AS VARIOUS OUTFLOW BOUNDARIES...AND
LINGERING INSTABILITY ARE KEEPING A FEW STORMS GOING AROUND CENTRAL
NC THIS EVENING...THOUGH MOST OF THE STORMS ARE OCCURRING AWAY FROM
TAF SITES AND SHOULD COME TO AN END BY MIDNIGHT. A LIGHT
WEST-SOUTHWESTERLY SURFACE WIND AND MOSTLY VFR CONDITIONS ARE
EXPECTED...THOUGH A FEW AREAS MAY SEE MVFR VSBYS BY DAYBREAK.
AN APPROACHING COLD FRONT WILL INITIATE SCATTERED STORMS BY EARLY
FRIDAY AFTERNOON...FIRST AROUND THE TRIAD THEN MOVING SOUTH AND EAST
TOWARD KRDU..KRWI AND KFAY. THE OCCURRENCE AND TIMING OF STORMS AT
INDIVIDUAL TERMINALS IS STILL UNCERTAIN AT THIS POINT...BUT THE
PRESENCE OF THE COLD FRONT AND UPPER LEVEL TROUGH LENDS ENOUGH
FORECAST CONFIDENCE FOR A MENTION OF THUNDERSTORMS IN THE TAFS AFTER
18Z.
LOOKING AHEAD:
AFTER THE PASSAGE OF THE COLD FRONT...HIGH PRESSURE WILL SLOWLY
BUILD INTO THE REGION AND STRENGTHEN...LEADING TO A TREND TOWARD
VFR CONDITIONS THROUGH EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS TULSA OK
1227 PM CDT FRI AUG 23 2013
.DISCUSSION...
THE 18Z TAF DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
BAND OF HIGH BASED SHOWERS SHOULD DISSIPATE BY 19 OR 20Z...AND VFR
CONDITIONS WILL PREVAIL AT ALL TAF SITES THRU MUCH OF THE PERIOD.
A STRAY SHOWER OR STORM COULD IMPACT ANY AIRPORT...BUT CHANCES ARE
TOO LOW TO MENTION. PERSISTENCE SUGGESTS FOG WILL REDUCE VSBYS AT
KBVO AND KFYV DOWN TO IFR RANGE ANYWHERE FROM 06Z TO 14Z TONIGHT
AND EARLY SATURDAY.
LACY
&&
.PREV DISCUSSION... /ISSUED 907 AM CDT FRI AUG 23 2013/
DISCUSSION...
UPPER AIR DATA AT 12Z SHOWS COOLER AND MORE MOIST CONDITIONS IN
THE MID LVLS COMPARED TO 24 HRS AGO...FROM 700MB UP TO 500MB. IN
THE LATE NIGHT AND EARLY MORNING...THIS MID LVL MOISTURE CREATES
SOME INSTABILITY DUE TO NOCTURNAL COOLING ABOVE THIS MOIST LAYER.
THIS HAS PRODUCED A FEW HIGH BASED SHOWERS AND A LIGHTNING STRIKE
OR TWO OVER EASTERN OKLAHOMA. HOWEVER...AS THE DAY CONTINUES THIS
MID LEVEL INSTABILITY WANES AND THUS THE SHOWERS SHOULD DISSIPATE
BY MIDDAY AS THE HRRR AND LOCAL WRF MODEL SUGGEST. GRIDS HAVE BEEN
UPDATED TO ACCOUNT FOR THE SMALL AREA OF PRECIP DOWN OVER EAST
CENTRAL OKLAHOMA.
LACY
PREV DISCUSSION... /ISSUED 709 AM CDT FRI AUG 23 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
PATCHY FOG AT TAF SITES KBVO/KXNA/KFYV TO MIX AWAY BY 15Z.
VFR ALL SITES UNTIL PATCHY FOG RETURNS AGAIN LATE TONIGHT
GENERALLY AFTER 06Z WITH POTENTIAL VISIBILITY BELOW 3 MILES
KFYV/KXNA.
PREV DISCUSSION... /ISSUED 339 AM CDT FRI AUG 23 2013/
DISCUSSION...
A STRONG RIDGE OF HIGH PRESSURE ALOFT WILL REMAIN OVER THE AREA
THROUGH THE ENTIRE FORECAST PERIOD. THIS WILL LEAD TO AN EXTENDED
STRETCH OF HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN. AN
ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE THE NEXT FEW
AFTERNOONS...MAINLY OVER THE HIGHER TERRAIN AREAS...BUT AREAL
COVERAGE WILL BE MUCH TOO LOW TO MENTION IN THE FORECAST.
AFTERNOON TEMPERATURES MAY INCH UP A BIT NEXT WEEK AS LOW LEVEL
WINDS LOSE THE EASTERLY COMPONENT THAT WILL BE PRESENT THE NEXT
FEW DAYS.
STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 73 94 74 94 / 0 10 0 10
FSM 73 95 74 95 / 0 10 0 10
MLC 72 95 73 95 / 10 10 10 10
BVO 69 93 70 93 / 0 10 0 10
FYV 67 91 68 91 / 0 10 0 10
BYV 69 91 70 91 / 0 10 0 10
MKO 71 94 72 94 / 0 10 0 10
MIO 70 92 71 92 / 0 10 0 10
F10 71 95 72 95 / 10 10 10 10
HHW 73 96 74 96 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
907 AM CDT FRI AUG 23 2013
.DISCUSSION...
UPPER AIR DATA AT 12Z SHOWS COOLER AND MORE MOIST CONDITIONS IN
THE MID LVLS COMPARED TO 24 HRS AGO...FROM 700MB UP TO 500MB. IN
THE LATE NIGHT AND EARLY MORNING...THIS MID LVL MOISTURE CREATES
SOME INSTABILITY DUE TO NOCTURNAL COOLING ABOVE THIS MOIST LAYER.
THIS HAS PRODUCED A FEW HIGH BASED SHOWERS AND A LIGHTNING STRIKE
OR TWO OVER EASTERN OKLAHOMA. HOWEVER...AS THE DAY CONTINUES THIS
MID LEVEL INSTABILITY WANES AND THUS THE SHOWERS SHOULD DISSIPATE
BY MIDDAY AS THE HRRR AND LOCAL WRF MODEL SUGGEST. GRIDS HAVE BEEN
UPDATED TO ACCOUNT FOR THE SMALL AREA OF PRECIP DOWN OVER EAST
CENTRAL OKLAHOMA.
LACY
&&
.PREV DISCUSSION... /ISSUED 709 AM CDT FRI AUG 23 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
PATCHY FOG AT TAF SITES KBVO/KXNA/KFYV TO MIX AWAY BY 15Z.
VFR ALL SITES UNTIL PATCHY FOG RETURNS AGAIN LATE TONIGHT
GENERALLY AFTER 06Z WITH POTENTIAL VISIBILITY BELOW 3 MILES
KFYV/KXNA.
PREV DISCUSSION... /ISSUED 339 AM CDT FRI AUG 23 2013/
DISCUSSION...
A STRONG RIDGE OF HIGH PRESSURE ALOFT WILL REMAIN OVER THE AREA
THROUGH THE ENTIRE FORECAST PERIOD. THIS WILL LEAD TO AN EXTENDED
STRETCH OF HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN. AN
ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE THE NEXT FEW
AFTERNOONS...MAINLY OVER THE HIGHER TERRAIN AREAS...BUT AREAL
COVERAGE WILL BE MUCH TOO LOW TO MENTION IN THE FORECAST.
AFTERNOON TEMPERATURES MAY INCH UP A BIT NEXT WEEK AS LOW LEVEL
WINDS LOSE THE EASTERLY COMPONENT THAT WILL BE PRESENT THE NEXT
FEW DAYS.
STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 94 73 94 74 / 10 0 10 0
FSM 95 73 95 74 / 10 0 10 0
MLC 95 72 95 73 / 10 10 10 10
BVO 93 69 93 70 / 10 0 10 0
FYV 91 67 91 68 / 10 0 10 0
BYV 91 69 91 70 / 10 0 10 0
MKO 94 71 94 72 / 10 0 10 0
MIO 92 70 92 71 / 10 0 10 0
F10 95 71 95 72 / 30 10 10 10
HHW 96 73 96 74 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
435 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION TONIGHT...TRIGGERING SHOWERS
AND THUNDERSTORMS BEFORE USHERING IN DRIER WEATHER FOR THE WEEKEND.
HIGH PRESSURE WILL BUILD BACK IN FOR THE FIRST PART OF THE
WEEK...BEGINNING A GRADUAL WARMING TREND. RETURNING SOUTHERLY FLOW
WILL GRADUALLY INCREASE MOISTURE ACROSS THE REGION...INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A SERIES OF
COLD FRONTS WILL MOVE THROUGH THE REGION LATE IN THE WEEK ELEVATING
RAIN CHANCES FURTHER.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 430 PM...AREA OF CONVECTION IS SHIFTING TO THE WRN CWFA AND
DYING OFF EAST OF I-77. HAVE UPDATED AFTERNOON AND EVENING POP TO
REFLECT THESE TRENDS. NOW HAVE HIGHEST POP FOLLOWING THE TRACK OF
THE CURRENT OUTFLOW BOUNDARY AND SPREADING ACROSS THE UPSTATE INTO
NE GA. ALSO HAVE HIGH POP SPREADING SW ACROSS THE NC MTNS AS WELL.
POP SIGNIFICANTLY REDUCED OVER THE I-77 CORRIDOR. SVR STORMS REMAIN
POSSIBLE AS THE STORMS MOVE INTO AN AREA WITH SIGNIFICANTLY HIGHER
DCAPE VALUES. TEMPS FELL SIGNIFICANTLY WITH THE LINE OF TSRA AND
HAVE FOLLOWED THESE TRENDS AS WELL...ALTHOUGH NOT AS DRAMATICALLY.
AS OF 230 PM EDT FRIDAY...A LINE OF SHOWERS AND THUNDERSTORMS HAS
DEVELOPED OVER THE WRN NC FOOTHILLS AND PIEDMONT. THE LINE IS BEING
FORCED BY LLVL SFC CONVERGENCE AND DIFFERENTIAL HEATING RESULTING
FROM THE APPROACH OF AN H5 SHORT WAVE WHICH THE RAP CURRENTLY HAS
LOCATED OVER NE TN AND SW VA. THE DEEP LAYER SHEAR ISN/T
STRONG...BUT THE AIRMASS AHEAD OF THE LINE IS QUITE UNSTABLE AND IT
ALREADY HAS A WELL ESTABLISHED REAR INFLOW JET PER THE TERMINAL
DOPPLER RADAR AT CHARLOTTE. THE NAM AND GFS BOTH STRENGTHEN SFC
CONVERGENCE AHEAD OF THE LINE. THEREFORE IT SHOULD CONTINUE TO MOVE
TO THE SOUTHEAST AND AT LEAST MAINTAIN ITSELF IF NOT GET STRONGER.
BUT IT SHOULD ALSO BUILD TO THE SOUTHWEST...OR NEW STORMS MAY
ORIGINATE OVER THE SC MTNS...AS THE LLVL WINDS BACK ACROSS MOST OF
THE UPSTATE AND EVEN INTO NE GA OVER THE NEXT COUPLE HOURS. AT THIS
RATE MOST LOCATIONS OVER THE FOOTHILLS AND PIEDMONT SHOULD GET INTO
THE ACT OVER THE NEXT 4 TO 6 HOURS AND POPS HAVE BEEN RAISED TO
LIKELY TO CATEGORICAL FOR THE REST OF THE DAY. DCAPE VALUES ARE HIGH
OVER THE UPSTATE...BUT DROP OFF RAPIDLY INTO NORTH CAROLINA. SO AS
THE LINE MOVE SOUTHWARD...IT/S TENDENCY TO PRODUCE STRONG OUTFLOW
SHOULD INCREASE.
STORMS SHOULD DIMINISH FROM NORTH TO SOUTH THIS EVENING. I THINK
THERE WILL ENOUGH CONVECTIVE DEBRIS AND MIXING EAST OF THE MTNS TO
PREVENT FOG FROM FORMING AGAIN. OVER THE MOUNTAINS WINDS ARE
EXPECTED TO DECOUPLE OVERNIGHT AS THE LLVL GRADIENT WINDS WILL BE
ORIENTED OUT OF THE NE...ORTHOGONAL TO THE HIGHER NC MTN CHAINS.
THEREFORE...THE MTN VALLEYS SHOULD SEE FOG AND STRATUS ONCE AGAIN.
COLD AIR DAMMING DEVELOPS FOR SATURDAY. THE MODELS STILL HAVE
1000-2000 SBCAPE VALUES OVER THE SOUTHERN ZONES. I/VE KEPT LOW END
CHANCE POPS ALONG THE UPPER SAVANNAH RIVER VALLEY AND OVER THE
SOUTHWEST AND CENTRAL NC MTNS. TYPICALLY IN THESE SITUATIONS MOST OF
THE DEVELOPMENT IS OVER THE SW MTNS AND ALONG THE EASTERN ESCARPMENT
OF THE BLUE RIDGE. CLOUDS MAY DISSIPATE IN THE DRIER AIR OVER THE
PIEDMONT AND ALONG THE TN LINE...WITH GENERALLY MOSTLY CLOUDY SKIES
EXPECTED ELSEWHERE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...A STRONG UPPER HIGH WILL BE CENTERED OVER MO
ON SATURDAY NIGHT....WHILE A POSITIVELY TILTED UPPER TROUGH WILL BE
JUST OFF THE EAST COAST. THIS TROUGH MOVES FARTHER OFF THE EAST
COAST ON SUNDAY...WHILE THE UPPER RIDGE REMAINS CENTERED OVER MO. ON
MONDAY THE UPPER RIDGE RETROGRESSES INTO KS.
A COLD FRONT TO OUR SOUTH WILL DRIFT FARTHER SOUTH ACROSS FL
SATURDAY NIGHT AND SUNDAY...WHILE DRIER AIR AND HIGH PRESSURE SPREAD
ACROSS THE CAROLINAS AND GA FROM THE NE. MODEL TIME HEIGHTS SHOW A
THINNING...LINGERING LAYER OF MOISTURE AT AROUND 850 MB BEHIND THE
FRONT. WITH JUST A WEAK EASTERLY UPSLOPE FLOW DEVELOPING AS WINDS
VEER IN THE LOW LEVELS...ONLY VERY SMALL POPS WILL BE CARRIED SUNDAY
EVENING AND LATE MONDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH
THE PERIOD...WITH A SLIGHT WARMING TREND ON MONDAY AS HEIGHTS RISE
ALOFT WITH THE PROGRESSION OF THE ATLANTIC TROUGH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...OVERALL A MUCH DRIER PATTERN FOR THE
EXTENDED THAN WHAT WE HAVE SEEN IN THE PAST FEW WEEKS. AN UPPER
RIDGE WILL BE FIRMLY ENTRENCHED OVER THE CENTRAL PLAINS BY MONDAY
NIGHT WHILE A SURFACE RIDGE WILL SHIFT SOUTHEASTWARD TOWARDS THE
ATLANTIC TO TAKE ON BERMUDA HIGH CHARACTERISTICS. THIS WILL SET UP A
WEAK SOUTHEASTERLY FLOW REGIME AT THE SURFACE...AND BY WEDNESDAY A
HIGH IN THE NORTHEAST WILL ALLOW A WEAK WEDGE TO BUILD IN OVER THE
APPALACHIANS AND ADVECT IN MODERATELY DRIER AIR. ANY CONVECTION WILL
FOLLOW A DIURNAL PATTERN...AND THEN WILL BE LIMITED MAINLY TO AREAS
OF UPSLOPE FLOW. AN EXPANDING SURFACE HIGH OVER THE GREAT LAKES WILL
PUSH MULTIPLE FRONTAL BOUNDARIES SOUTHWARD THROUGH THE CWA BY THE
END OF THE WEEK...INCREASING RAIN CHANCES ONCE AGAIN. RISING HEIGHTS
DUE TO THE UPPER LEVEL RIDGE WILL ALLOW HIGH TEMPERATURES TO
MODERATE BACK TO NORMAL LEVELS...IN THE MID TO HIGH 80S...FOR MOST
OF NEXT WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...THE LINE OF THUNDERSTORMS WEAKENED AND SPLIT THE AIRFIELD.
CHC FOR ADDITIONAL ACTIVITY NEAR THE AIRPORT IS LOW THIS EVENING...
SO WILL REMOVE MENTION...BUT WATCH FOR NEEDED AMD. WINDS SHUD STAY
LIGHT FROM THE NORTH INTO THE EVENING. IN FACT...SHOULD ONLY SEE SCT
LOW VFR CLOUDS UNLESS MORE CELLS DEVELOP. LATER TONIGHT AN MVFR
STRATO-CU DECK MAY MOVE IN AS THE TRUE SFC OLD FRONT ARRIVES. THE
RAP AND OUR LOCAL WRF ARW DO THIS AND I/VE ADDED A PERIOD OF MVFR
CIGS FROM 09-14 UTC TONIGHT AND TMRW. WINDS WILL VEER FROM NW TO NE
AS THE FRONT MOVES THROUGH.
ELSEWHERE...A LINE OF THUNDERSTORMS WILL DROP SOUTHEAST AND SHUD
AFFECT KGSP/KGMU THIS AFTERNOON AND POSSIBLY KAVL/KAND. KHKY LOOKS
TO BE OUT OF DANGER...BUT AN ADDITIONAL CELL COULD DEVELOP LATER.
WINDS WILL GO NORTH BEHIND THE GUST FRONT ASSOCIATED WITH THE LINE
OF STORMS. THEN LOW VFR CLEARS OUT UNTIL LATER TONIGHT. LATER
TONIGHT MVFR CIGS WILL DEVELOP OVER NC...BUT THEY MAY NOT MAKE IT
INTO THE UPSTATE. THEREFORE NO MVFR CIGS WERE CARRIED AT THE SOUTH
CAROLINA TAF SITES. AT KAVL THE WINDS SHOULD BE COME LIGHT LATE
TONIGHT AS THE FRONT IS MOVING IN FROM THE NE. THIS WILL SUPPORT
ANOTHER NIGHT WITH STRATUS AND FOG. WINDS WILL BECOME RATHER BRISK
OUT OF THE NORTHEAST AFTER SUNRISE. I WOULDN/T BE SURPRISED TO SEE
SOME GUSTS UP TO 20 KTS OVER THE UPSTATE AND AT KCLT.
OUTLOOK...A DRIER PATTERN IS EXPECTED AS HIGH PRESSURE GRADUALLY
BUILDS IN FROM THE NORTH OVER THE WEEKEND.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 81% HIGH 95%
KGSP HIGH 100% HIGH 91% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 67% LOW 56% MED 67%
KHKY HIGH 100% HIGH 80% LOW 52% HIGH 95%
KGMU HIGH 100% HIGH 91% HIGH 95% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...MCAVOY/RWH
SHORT TERM...JAT
LONG TERM...VISIN
AVIATION...MCAVOY/RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
229 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION TONIGHT...TRIGGERING SHOWERS
AND THUNDERSTORMS BEFORE USHERING IN DRIER WEATHER FOR THE WEEKEND.
HIGH PRESSURE WILL BUILD BACK IN FOR THE FIRST PART OF THE
WEEK...BEGINNING A GRADUAL WARMING TREND. RETURNING SOUTHERLY FLOW
WILL GRADUALLY INCREASE MOISTURE ACROSS THE REGION...INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A SERIES OF
COLD FRONTS WILL MOVE THROUGH THE REGION LATE IN THE WEEK ELEVATING
RAIN CHANCES FURTHER.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 230 PM EDT FRIDAY...A LINE OF SHOWERS AND THUNDERSTORMS HAS
DEVELOPED OVER THE WRN NC FOOTHILLS AND PIEDMONT. THE LINE IS BEING
FORCED BY LLVL SFC CONVERGENCE AND DIFFERENTIAL HEATING RESULTING
FROM THE APPROACH OF AN H5 SHORT WAVE WHICH THE RAP CURRENTLY HAS
LOCATED OVER NE TN AND SW VA. THE DEEP LAYER SHEAR ISN/T
STRONG...BUT THE AIRMASS AHEAD OF THE LINE IS QUITE UNSTABLE AND IT
ALREADY HAS A WELL ESTABLISHED REAR INFLOW JET PER THE TERMINAL
DOPPLER RADAR AT CHARLOTTE. THE NAM AND GFS BOTH STRENGTHEN SFC
CONVERGENCE AHEAD OF THE LINE. THEREFORE IT SHOULD CONTINUE TO MOVE
TO THE SOUTHEAST AND AT LEAST MAINTAIN ITSELF IF NOT GET STRONGER.
BUT IT SHOULD ALSO BUILD TO THE SOUTHWEST...OR NEW STORMS MAY
ORIGINATE OVER THE SC MTNS...AS THE LLVL WINDS BACK ACROSS MOST OF
THE UPSTATE AND EVEN INTO NE GA OVER THE NEXT COUPLE HOURS. AT THIS
RATE MOST LOCATIONS OVER THE FOOTHILLS AND PIEDMONT SHOULD GET INTO
THE ACT OVER THE NEXT 4 TO 6 HOURS AND POPS HAVE BEEN RAISED TO
LIKELY TO CATEGORICAL FOR THE REST OF THE DAY. DCAPE VALUES ARE HIGH
OVER THE UPSTATE...BUT DROP OFF RAPIDLY INTO NORTH CAROLINA. SO AS
THE LINE MOVE SOUTHWARD...IT/S TENDENCY TO PRODUCE STRONG OUTFLOW
SHOULD INCREASE.
STORMS SHOULD DIMINISH FROM NORTH TO SOUTH THIS EVENING. I THINK
THERE WILL ENOUGH CONVECTIVE DEBRIS AND MIXING EAST OF THE MTNS TO
PREVENT FOG FROM FORMING AGAIN. OVER THE MOUNTAINS WINDS ARE
EXPECTED TO DECOUPLE OVERNIGHT AS THE LLVL GRADIENT WINDS WILL BE
ORIENTED OUT OF THE NE...ORTHOGONAL TO THE HIGHER NC MTN CHAINS.
THEREFORE...THE MTN VALLEYS SHOULD SEE FOG AND STRATUS ONCE AGAIN.
COLD AIR DAMMING DEVELOPS FOR SATURDAY. THE MODELS STILL HAVE
1000-2000 SBCAPE VALUES OVER THE SOUTHERN ZONES. I/VE KEPT LOW END
CHANCE POPS ALONG THE UPPER SAVANNAH RIVER VALLEY AND OVER THE
SOUTHWEST AND CENTRAL NC MTNS. TYPICALLY IN THESE SITUATIONS MOST OF
THE DEVELOPMENT IS OVER THE SW MTNS AND ALONG THE EASTERN ESCARPMENT
OF THE BLUE RIDGE. CLOUDS MAY DISSIPATE IN THE DRIER AIR OVER THE
PIEDMONT AND ALONG THE TN LINE...WITH GENERALLY MOSTLY CLOUDY SKIES
EXPECTED ELSEWHERE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...A STRONG UPPER HIGH WILL BE CENTERED OVER MO
ON SATURDAY NIGHT....WHILE A POSITIVELY TILTED UPPER TROUGH WILL BE
JUST OFF THE EAST COAST. THIS TROUGH MOVES FARTHER OFF THE EAST
COAST ON SUNDAY...WHILE THE UPPER RIDGE REMAINS CENTERED OVER MO. ON
MONDAY THE UPPER RIDGE RETROGRESSES INTO KS.
A COLD FRONT TO OUR SOUTH WILL DRIFT FARTHER SOUTH ACROSS FL
SATURDAY NIGHT AND SUNDAY...WHILE DRIER AIR AND HIGH PRESSURE SPREAD
ACROSS THE CAROLINAS AND GA FROM THE NE. MODEL TIME HEIGHTS SHOW A
THINNING...LINGERING LAYER OF MOISTURE AT AROUND 850 MB BEHIND THE
FRONT. WITH JUST A WEAK EASTERLY UPSLOPE FLOW DEVELOPING AS WIDNS
VEER IN THE LOW LEVELS...ONLY VERY SMALL POPS WILL BE CARRIED LATE
MONDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH THE PERIOD...WITH
A SLIGHT WARMING TREND ON MONDAY AS HEIGHTS RISE ALOFT WITH THE
PROGRESSION OF THE ATLANTIC TROUGH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...OVERALL A MUCH DRIER PATTERN FOR THE
EXTENDED THAN WHAT WE HAVE SEEN IN THE PAST FEW WEEKS. AN UPPER
RIDGE WILL BE FIRMLY ENTRENCHED OVER THE CENTRAL PLAINS BY MONDAY
NIGHT WHILE A SURFACE RIDGE WILL SHIFT SOUTHEASTWARD TOWARDS THE
ATLANTIC TO TAKE ON BERMUDA HIGH CHARACTERISTICS. THIS WILL SET UP A
WEAK SOUTHEASTERLY FLOW REGIME AT THE SURFACE...AND BY WEDNESDAY A
HIGH IN THE NORTHEAST WILL ALLOW A WEAK WEDGE TO BUILD IN OVER THE
APPALACHIANS AND ADVECT IN MODERATELY DRIER AIR. ANY CONVECTION WILL
FOLLOW A DIURNAL PATTERN...AND THEN WILL BE LIMITED MAINLY TO AREAS
OF UPSLOPE FLOW. AN EXPANDING SURFACE HIGH OVER THE GREAT LAKES WILL
PUSH MULTIPLE FRONTAL BOUNDARIES SOUTHWARD THROUGH THE CWA BY THE
END OF THE WEEK...INCREASING RAIN CHANCES ONCE AGAIN. RISING HEIGHTS
DUE TO THE UPPER LEVEL RIDGE WILL ALLOW HIGH TEMPERATURES TO
MODERATE BACK TO NORMAL LEVELS...IN THE MID TO HIGH 80S...FOR MOST
OF NEXT WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A LINE OF THUNDERSTORMS IS ORGANIZING 40 TO 50 MILES
NORTHWEST OF THE AIRFIELD. IT SHOULD CONTINUE MOVING SOUTHEAST AND
WILL LIKELY ACCELERATE A LITTLE AS IT DOES. TEMPO THUNDER HAS BEEN
MOVED UP AN HOUR...FROM 19-22 UTC. STORMS ARE SHOWING 30-35KT
INBOUNDS ON TDWR. THE LINE SHOULD STRENGTHEN SOME AS IT APPROACHES
AND I/VE ADDED A PERIOD OF 35 KT GUSTS TO THE TAF. I WENT
VARIABLE...THOUGH THE STRONGEST WINDS ARE LIKELY TO BE ORIENTED OUT
OF THE NORTH. SCT SHRA AND A FEW TSTMS WILL PERSIST INTO THE LATE
EVENING HOURS. LATER TONIGHT AN MVFR STRATO-CU DECK MAY MOVE IN AS
THE TRUE SFC OLD FRONT ARRIVES. THE RAP AND OUR LOCAL WRF ARW DO
THIS AND I/VE ADDED A PERIOD OF MVFR CIGS FROM 09-14 UTC TONIGHT AND
TWRW. WINDS WILL VEER FROM NW TO NE AS THE FRONT MOVES THROUGH.
ELSEWHERE...A LINE OF THUNDERSTORMS WILL DROP SOUTHEAST ACROSS THE
NC AND SC PIEDMONT THIS AFTERNOON AND EVENING. THE QUESTION IS HOW
FAR TO THE SOUTHWEST THE LINE WILL BUILD. THE MODELS HAVE GOOD
CONVERGENCE WELL INTO THE UPSTATE...SO I THINK THE LINE WILL BUILD
TO THE SOUTHWEST AND I/VE ADDED TEMPO THUNDER IN AT KGMU/KGSP
STARTING AT 20 UTC. THE LINE IS PRACTICALLY ON TOP OF HKY AND THEY
HAVE A TEMPO FOR THE NEXT COUPLE HOURS. I/M NOT AS CONFIDENT OF KAND
AND TEMPO WAS LEFT OUT OF THAT SITE. KAVL WILL PROBABLY SEE
SOMETHING SO THEY GOT A TEMPO AS WELL. LATER TONIGHT MVFR CIGS WILL
DEVELOP OVER NC...BUT THEY MAY NOT MAKE IT INTO THE UPSTATE.
THEREFORE NO MVFR CIGS WERE CARRIED AT THE SOUTH CAROLINA TAF SITES.
AT KAVL THE WINDS SHOULD BE COME LIGHT LATE TONIGHT AS THE FRONT IS
MOVING IN FROM THE NE. THIS WILL SUPPORT ANOTHER NIGHT WITH STRATUS
AND FOG. WINDS WILL BECOME RATHER BRISK OUT OF THE NORTHEAST AFTER
SUNRISE. I WOULDN/T BE SURPRISED TO SEE SOME GUSTS UP TO 20 KTS OVER
THE UPSTATE AND AT KCLT.
OUTLOOK...A DRIER PATTERN IS EXPECTED AS HIGH PRESSURE GRADUALLY
BUILDS IN FROM THE NORTH OVER THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 85% HIGH 85%
KGSP HIGH 100% HIGH 100% HIGH 80% HIGH 97%
KAVL HIGH 100% MED 77% LOW 51% LOW 56%
KHKY HIGH 100% HIGH 94% LOW 42% HIGH 81%
KGMU HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...VISIN
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
201 PM EDT FRI AUG 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION TONIGHT...TRIGGERING SHOWERS
AND THUNDERSTORMS BEFORE USHERING IN DRIER WEATHER FOR THE WEEKEND.
HIGH PRESSURE WILL BUILD BACK IN FOR THE FIRST PART OF THE
WEEK...BEGINNING A GRADUAL WARMING TREND. RETURNING SOUTHERLY FLOW
WILL GRADUALLY INCREASE MOISTURE ACROSS THE REGION...INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A SERIES OF
COLD FRONTS WILL MOVE THROUGH THE REGION LATE IN THE WEEK ELEVATING
RAIN CHANCES FURTHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EDT FRIDAY...FOG AND STRATUS CONTINUES TO BURN OFF THIS
MORNING...THOUGH IT IS LINGERING ACROSS THE NC MTN VALLEYS AND OVER
A FEW LOW SPOTS OUT ACROSS THE FOOTHILLS AND PIEDMONT. FORECAST
REASONING FOR THE AFTERNOON HOURS HASN/T CHANGED MUCH. A SHORT WAVE
WILL CROSS THE REGION BETWEEN 21-00 UTC. CAPE VALUES WILL BE FAIRLY
HIGH...THOUGH LAPSE RATES WILL BE WEAK. ALSO...THE SPC FORECAST
MESOANALYSIS FOR THE FORECAST AREA HAS EFFECTIVE BULK SHEAR VALUES
UNDER 20 KTS THROUGH THE MID AFTN HOURS. THE VARIOUS CONVECTIVE
ALLOWING MODELS DON/T HAVE MUCH OVER OUR AREA...FAVORING MORE
VIGOROUS DEVELOPMENT OVER ERN NC AND SRN VA WHERE THE DEEP LAYER
SHEAR IS STRONGER. CONSIDERING ALL THIS I AM NOT GOING TO UP POPS
INTO THE LIKELY RANGE THIS AFTN. I THINK WE WILL SEE DECENT
COVERAGE...BUT I DON/T THINK THE FORCING SUPPORTS ANY ESCALATION OF
WHAT WE HAVE IN THERE ALREADY.
AS OF 700 AM EDT...THE FOG FORECAST REMAINS CHALLENGING THIS
MORNING...WITH MANY LOCATIONS THAT HAVE WET GROUND SEEING VSBY QUITE
VARIABLE AND DIPPING INTO DENSE FOG RANGE...ESPECIALLY THE FOOTHILLS
AND MTN VALLEYS. HOWEVER...MID AND HIGH CLOUDS ARE THICKENING ALOFT
WHICH COULD PUT THE BREAKS ON MORE WIDESPREAD FOG DEVELOPMENT...AND
MUCH OF THE 1/4SM VSBY HAS BEEN SHALLOWER GROUND FOG. AN SPS HAS
BEEN ISSUED FOR MTNS/FOOTHILLS...AND ADDITIONAL FOG/PATCHY DENSE
WORDING HAS BEEN ADDED TO THE FORECAST.
OTHERWISE...THE FORECAST REMAINS ON TRACK WITH WATER VAPOR IMAGERY
SHOWING A SHORTWAVE MOVING SE FROM THE OH VALLEY EARLY THIS
MORNING...ATOP AN ASSOCIATED SFC COLD FRONT. THE BOUNDARY WILL MOVE
INTO THE FORECAST AREA THROUGH THE DAY...WITH UPPER JET DIVERGENCE
GRADUALLY SHARPENING UP OVERHEAD...ALONG WITH IMPROVING LOW LEVEL
CONVERGENCE ALONG THE FRONTAL ZONE. THIS FORCING SHOULD COMBINE WITH
SFC BASED INSTABILITY REACHING 2500 TO 3000 J/KG CAPE THIS AFTN
ACROSS THE SE HALF OF THE FORECAST AREA. ANTICIPATE FAIRLY DECENT
SCATTERED COVERAGE THROUGHOUT THIS AFTN...BUT WITH THE BEST CHANCE
OF STRONG TO SEVERE THUNDERSTORMS ALONG AND SE OF THE INTERSTATE 85
CORRIDOR. WIND SHEAR WILL BE FAIRLY LIMITED UP THE COLUMN...BUT WITH
JUST ENOUGH DIRECTIONAL/SPEED SHEAR FOR WEAK MULTI CELL DEVELOPMENT
IN THE DEEP LAYER FORCING. WILL HIGHLIGHT THE POTENTIAL IN THE HWO.
TEMPS AHEAD OF THE FRONTAL ZONE THIS AFTN WILL REACH MAXES AT OR
SLIGHTLY ABOVE CLIMATE AVERAGES.
THE BOUNDARY WILL SETTLE S OF THE FORECAST AREA TONIGHT. DEEP LAYER
N TO NW FLOW WILL SET UP BEHIND THE FRONT OVERNIGHT...WITH DRYING AT
MID AND UPPER LEVELS. HOWEVER...SOME BL TO 850 MB MOISTURE WILL
LIKELY LINGER IN THE NRLY FLOW FOR SOME ATTENDANT CLOUDS TO DEVELOP
AND KEEP MINS ABOVE NORMAL VALUES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 AM EDT FRIDAY...AS UPPER TROF CONTINUES TO MOVE OFF THE
EAST COAST...SURFACE COLD FRONT WILL HAVE PUSHED INTO THE EXTREME
SOUTHEAST NEAR THE I10 CORRIDOR. SFC HIGH PRESSURE WILL BEGIN TO
BUILD IN ACROSS THE GREAT LAKES REGION BEHIND THE EXITING UPPER
TROF. DUE TO THE WEAK NATURE OF THE BOUNDARY THAT PASSED THROUGH
THE PREVIOUS DAY...SFC DEWPOINTS WILL STILL BE IN THE UPPER 60S
ACROSS THE NC/SC PIEDMONT REGIONS THUS KEEPING POTENTIAL FOR SOME
SCATTERED SHOWERS ELEVATED DURING THE DAY ON SATURDAY. FURTHER WEST
ACROSS THE MOUNTAINS...EVEN THOUGH MOISTURE IS SLIGHTLY
LOWER...DYNAMIC UPSLOPE FORCING COULD PROVIDE ENOUGH LIFT FOR SOME
CONVECTION INTO THE AFTERNOONS HOURS. THUS FOR SATURDAY...KEPT
SLIGHT CHANCE POPS ACROSS THE PIEDMONT REGIONS AS DIURNAL HEATING
WILL COMBINE WITH ABOVE MENTIONED UPPER 60S DEWPOINTS TO CREATE AT
LEAST SOME SURFACE BASED INSTABILITY...THEREFORE SHOWERS COULD NOT
BE RULED OUT. AS FOR THE HIGH TERRAIN...HIGHLIGHTED SLIGHTLY HIGHER
CHANCE POPS DUE TO UPSLOPE COMPONENT. TAPERED POPS BACK DURING THE
OVERNIGHT HOURS ACROSS THE ENTIRE REGION. TEMPERATURES ON SATURDAY
LOOK TO BE A FEW DEGREES BELOW NORMAL.
SUNDAY IS LOOKING LIKE A RATHER NICE DAY ACROSS THE REGION. SFC
HIGH PRESSURE WILL SLOWLY DRIFT SOUTHEAST DURING THE EARLY MORNING
HOURS...THUS STRENGTHENING NORTHEAST FLOW ALLOWING A WEAK WEDGE TO
DOMINATE THE REGION. AS DRIER AIR IS ADVECTED IN...MODEL GUIDANCE
REMAINS IN GOOD AGREEMENT WITH REGARDS TO LACK OF INSTABILITY AS
MOISTURE AXIS SHIFTS SOUTH. THEREFORE KEPT POPS OUT OF THE FORECAST
FOR SUNDAY ACROSS THE ENTIRE REGION. ALTHOUGH TEMPERATURES WILL
REMAIN IN THE LOWER 80S ON SUNDAY...IT SHOULD FEEL MORE PLEASANT
OUTSIDE AS LOWER DEWPOINTS REDUCE HUMIDITY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 200 PM EDT FRIDAY...OVERALL A MUCH DRIER PATTERN FOR THE
EXTENDED THAN WHAT WE HAVE SEEN IN THE PAST FEW WEEKS. AN UPPER
RIDGE WILL BE FIRMLY ENTRENCHED OVER THE CENTRAL PLAINS BY MONDAY
NIGHT WHILE A SURFACE RIDGE WILL SHIFT SOUTHEASTWARD TOWARDS THE
ATLANTIC TO TAKE ON BERMUDA HIGH CHARACTERISTICS. THIS WILL SET UP A
WEAK SOUTHEASTERLY FLOW REGIME AT THE SURFACE...AND BY WEDNESDAY A
HIGH IN THE NORTHEAST WILL ALLOW A WEAK WEDGE TO BUILD IN OVER THE
APPALACHIANS AND ADVECT IN MODERATELY DRIER AIR. ANY CONVECTION WILL
FOLLOW A DIURNAL PATTERN...AND THEN WILL BE LIMITED MAINLY TO AREAS
OF UPSLOPE FLOW. AN EXPANDING SURFACE HIGH OVER THE GREAT LAKES WILL
PUSH MULTIPLE FRONTAL BOUNDARIES SOUTHWARD THROUGH THE CWA BY THE
END OF THE WEEK...INCREASING RAIN CHANCES ONCE AGAIN. RISING HEIGHTS
DUE TO THE UPPER LEVEL RIDGE WILL ALLOW HIGH TEMPERATURES TO
MODERATE BACK TO NORMAL LEVELS...IN THE MID TO HIGH 80S...FOR MOST
OF NEXT WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A LINE OF THUNDERSTORMS IS ORGANIZING 40 TO 50 MILES
NORTHWEST OF THE AIRFIELD. IT SHOULD CONTINUE MOVING SOUTHEAST AND
WILL LIKELY ACCELERATE A LITTLE AS IT DOES. TEMPO THUNDER HAS BEEN
MOVED UP AN HOUR...FROM 19-22 UTC. STORMS ARE SHOWING 30-35KT
INBOUNDS ON TDWR. THE LINE SHOULD STRENGTHEN SOME AS IT APPROACHES
AND I/VE ADDED A PERIOD OF 35 KT GUSTS TO THE TAF. I WENT
VARIABLE...THOUGH THE STRONGEST WINDS ARE LIKELY TO BE ORIENTED OUT
OF THE NORTH. SCT SHRA AND A FEW TSTMS WILL PERSIST INTO THE LATE
EVENING HOURS. LATER TONIGHT AN MVFR STRATO-CU DECK MAY MOVE IN AS
THE TRUE SFC OLD FRONT ARRIVES. THE RAP AND OUR LOCAL WRF ARW DO
THIS AND I/VE ADDED A PERIOD OF MVFR CIGS FROM 09-14 UTC TONIGHT AND
TWRW. WINDS WILL VEER FROM NW TO NE AS THE FRONT MOVES THROUGH.
ELSEWHERE...A LINE OF THUNDERSTORMS WILL DROP SOUTHEAST ACROSS THE
NC AND SC PIEDMONT THIS AFTERNOON AND EVENING. THE QUESTION IS HOW
FAR TO THE SOUTHWEST THE LINE WILL BUILD. THE MODELS HAVE GOOD
CONVERGENCE WELL INTO THE UPSTATE...SO I THINK THE LINE WILL BUILD
TO THE SOUTHWEST AND I/VE ADDED TEMPO THUNDER IN AT KGMU/KGSP
STARTING AT 20 UTC. THE LINE IS PRACTICALLY ON TOP OF HKY AND THEY
HAVE A TEMPO FOR THE NEXT COUPLE HOURS. I/M NOT AS CONFIDENT OF KAND
AND TEMPO WAS LEFT OUT OF THAT SITE. KAVL WILL PROBABLY SEE
SOMETHING SO THEY GOT A TEMPO AS WELL. LATER TONIGHT MVFR CIGS WILL
DEVELOP OVER NC...BUT THEY MAY NOT MAKE IT INTO THE UPSTATE.
THEREFORE NO MVFR CIGS WERE CARRIED AT THE SOUTH CAROLINA TAF SITES.
AT KAVL THE WINDS SHOULD BE COME LIGHT LATE TONIGHT AS THE FRONT IS
MOVING IN FROM THE NE. THIS WILL SUPPORT ANOTHER NIGHT WITH STRATUS
AND FOG. WINDS WILL BECOME RATHER BRISK OUT OF THE NORTHEAST AFTER
SUNRISE. I WOULDN/T BE SURPRISED TO SEE SOME GUSTS UP TO 20 KTS OVER
THE UPSTATE AND AT KCLT.
OUTLOOK...A DRIER PATTERN IS EXPECTED AS HIGH PRESSURE GRADUALLY
BUILDS IN FROM THE NORTH OVER THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 85% HIGH 85%
KGSP HIGH 100% HIGH 100% HIGH 80% HIGH 97%
KAVL HIGH 100% MED 77% LOW 51% LOW 56%
KHKY HIGH 100% HIGH 94% LOW 42% HIGH 81%
KGMU HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG
NEAR TERM...HG/MCAVOY
SHORT TERM...CDG
LONG TERM...VISIN
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1004 PM CDT SAT AUG 24 2013
.UPDATE...
POPS AND WEATHER GRIDS FOR TONIGHT AND SUNDAY.
&&
.DISCUSSION...
EQUIPMENT ISSUE OF NOTE...THE GALVESTON TEMPERATURE IS TOO COOL.
TECHNICIANS WILL CHECK OUT THE EQUIPMENT SOMETIME DURING THE NEXT
24 TO 48 HOURS.
00Z ANALYSIS AND MODEL FORECASTS PLACE THE EASTERLY WAVE OVER THE
NORTHERN GULF ALONG THE LA COAST INTO THE CENTRAL GULF OF MEXICO.
BOTH THE RAP AND NAM12 700 TO 300 MEAN LAYER FORECAST SHOWS THAT A
SMALLER LOW PRESSURE TROUGH WILL APPROACH THE UPPER TEXAS COAST
OVERNIGHT TONIGHT WITH THE MAIN WAVE THEN MOVING TO ALONG THE
COAST DURING THE MID MORNING SUNDAY. BOTH MODELS KEEP THE BEST
LAYER MOISTURE AND LIFT ALONG THE INTERSTATE 10 CORRIDOR SOUTH
DURING THE MIDDAY AND AFTERNOON PERIOD. THE RIDGE TO THE NORTH MAY
BE TOO MUCH FOR THE WAVE TO OVERCOME. EXPECT THE MAIN BULK OF THE
RAIN CHANCES WILL OCCUR ALONG AND EAST OF THE WAVE AXIS...AND
THERE MAY WELL BE A FAIRLY BIG DISCONTINUITY BETWEEN NO TO
ISOLATED COVERAGE AND BE BULK OF THE ACTIVITY. FOR THAT REASON
WILL ADJUST THE POPS DOWNWARD OVER THE INLAND AREAS TONIGHT AND
FROM THE INTERSTATE 10 CORRIDOR NORTHWARD ON SUNDAY. ADJUSTED THE
POPS SLIGHTLY DOWNWARD ELSEWHERE AS WELL BOTH PERIODS.
40
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT SAT AUG 24 2013/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
KCLL/KUTS/KCXO...OVER SHOULD HAVE VFR CIGS WITH MAYBE AN HOUR OR
SO OF 5SM AT KCXO IN THE MORNING BUT WILL NOT MENTION IN TAF.
CONVECTION WILL BE MAIN ISSUE TOMORROW AS TROPICAL WAVE MOVES
INLAND SLOWLY. MAY SEE A FEW SHOWERS A KCXO BUT THINK MAJORITY OF
CONVECTION STAYS SOUTH OF THESE TERMINALS.
KIAH/KHOU/KSGR...EXPECT VFR CIGS TONIGHT BUT INCREASING CLOUDS
THROUGH THE MORNING. MAIN ISSUE WILL BE THE ONSET OF CONVECTION
WITH TROPICAL WAVE MOVING INLAND. TROPICAL MOISTURE MAY BE SLOW TO
MOVE INLAND SO THINK KIAH WILL BE ON EDGE OF CONVECTION. WILL
MENTION VCSH FOR ALL TAFS STARTING EARLIER IN THE DAY FOR
KHOU/KSGR AND IN THE AFTERNOON FOR KIAH. WILL NEED TO EVALUATE
VCTS FOR KHOU/KSGR FOR 17Z-20Z TIME FRAME FOR 06Z TAFS BASED ON
00Z MODEL RUNS. RIGHT NOW MORE CONFIDENT IN TS FOR KHOU/KSGR THAN
KIAH. THINK 00Z MODEL RUNS WILL GIVE BETTER IDEA. ALSO INCREASED
WIND FOR AFTERNOON AS PRESSURE GRADIENT TIGHTENS.
KLBX/KGLS...MAIN ISSUE WILL BE SHRA DEVELOPING IN THE MORNING AND
MOVING INLAND AS TROPICAL WAVE MOVES INLAND. WILL START VCSH AT
09Z FOR BOTH TERMINALS THEN DEVELOPING VCTS BY 15Z WITH MORE
DAYTIME HEATING AND INCREASED TROPICAL MOISTURE. THINK THERE COULD
BE A GOOD PERIOD OF SCT TSRA FOR BOTH TERMINALS FROM 15-21Z. WILL
HOLD OFF ON TEMPO TSRA AND USE 00Z MODELS TO EVALUATE IF THERE
WILL BE A TIME FRAME FOR MORE PRONOUNCED TSRA.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 75 94 74 / 10 30 20 40 20
HOUSTON (IAH) 77 92 75 91 75 / 10 40 40 50 20
GALVESTON (GLS) 79 87 79 87 80 / 30 50 60 60 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SPOKANE WA
815 AM PDT Fri Aug 23 2013
.SYNOPSIS...
A potent storm system will bring scattered showers and
thunderstorms through the region today. Unsettled conditions will
continue across the Inland Northwest over the weekend and majority
of next week as a moist southwest flow pattern remains in place.
&&
.DISCUSSION...
Update to the forecast to increase the chances of showers and
thunderstorms. Upper low is currently spinning over our area and
will eject northward through the day. Shower and thunderstorm
coverage will gradually advance northward through the day as well,
with clearing skies moving up from Oregon later this afternoon.
I will be looking at the potential for stronger thunderstorms this
afternoon. Right now the HRRR does show moderately strong storms
this afternoon over the north. But the extensive cloud cover would
likely limit heating, so that HRRR idea may be overdone. Will
address this issue in another hour or 2. RJ
&&
.AVIATION...
12Z TAFS: Scattered showers and embedded thunderstorms will
continue to expand across central and eastern WA and north ID
this morning as an upper shortwave trof tracks northeast from
the Cascades. Primarily VFR conditions are expected, though brief
MVFR conditions and gusty winds are possible in heavy
showers/storms. As morning transitions to afternoon the
showers/thunderstorm threat is expected to translate northward,
with the west and southern TAF sites drying out and eventually all
TAF sites dry out by late afternoon. However look for breezy
conditions, with occasional gusts to 20kts. Winds abate in the
00-06Z time frame. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 81 58 82 60 81 58 / 60 10 10 20 20 20
Coeur d`Alene 81 54 83 57 82 55 / 40 10 10 20 20 20
Pullman 82 52 82 54 81 51 / 30 10 10 20 20 20
Lewiston 88 61 90 62 87 61 / 20 10 10 20 20 20
Colville 83 52 86 55 86 52 / 70 20 10 30 20 30
Sandpoint 80 49 81 51 80 51 / 60 10 10 20 20 20
Kellogg 79 53 83 55 81 54 / 40 10 10 20 20 20
Moses Lake 85 58 83 60 82 57 / 20 10 10 30 20 20
Wenatchee 85 60 82 62 80 59 / 50 10 20 20 20 20
Omak 83 57 84 59 85 57 / 70 10 20 20 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 2 PM PDT this afternoon for Northern and
Central Idaho Panhandle (Zone 101).
WA...Red Flag Warning until 2 PM PDT this afternoon for East
Washington Northeast (Zone 686)-East Washington Northern
Columbia Basin (Zone 673)-East Washington Okanogan
Highlands (Zone 687)-East Washington Palouse and Spokane
Area (Zone 674).
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
644 AM PDT Fri Aug 23 2013
.SYNOPSIS...
A potent storm system will bring scattered showers and
thunderstorms through the region today. Unsettled conditions will
continue across the Inland Northwest over the weekend and majority
of next week as a moist southwest flow pattern remains in place.
&&
.DISCUSSION...
Early morning update: a shortwave trough is coming into the
Cascades of Washington and Columbia Basin and, combined with a
theta-e ridge bent across the northern mountains through the
Basin, scattered showers have been on the increase over the past
several hours. There have been a few embedded thunderstorms too.
The recent short-range RUC and HRRR keep a fair amount of the
activity along and north of the I-90 corridor, with more isolated
activity across the Palouse southward. I have updated the forecast
to reduce the PoPs in that latter locations as well as to slightly
delay the increase into the Spokane/C`dA areas.
However radar trends do show increasing activity, with "popcorn
showers" and thunderstorms expanding across the Moses Lake and
Upper Columbia Basin zones, skirting western Spokane county at
this hour. While most areas won`t see the day "washed-out", be
prepared for isolated to widely scattered showers or thunderstorm.
There is a fair amount of clear skies south and east of this
region, so the heating of the day and incoming trough should help
increase the shower/thunderstorm threat in areas where it is not
yet occurring. However the speed of the shortwave trough passage
may keep this activity isolated to widely scattered. Yet storms
may still be capable of producing abundant lightning with little
significant precipitation amounts. So the Red Flag Warning
continues. /J. Cote`
&&
.AVIATION...
12Z TAFS: Scattered showers and embedded thunderstorms will
continue to expand across central and eastern WA and north ID
this morning as an upper shortwave trof tracks northeast from
the Cascades. Primarily VFR conditions are expected, though brief
MVFR conditions and gusty winds are possible in heavy
showers/storms. As morning transitions to afternoon the
showers/thunderstorm threat is expected to translate northward,
with the west and southern TAF sites drying out and eventually all
TAF sites dry out by late afternoon. However look for breezy
conditions, with occasional gusts to 20kts. Winds abate in the
00-06Z time frame. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 81 58 82 60 81 58 / 20 10 10 20 20 20
Coeur d`Alene 81 54 83 57 82 55 / 20 10 10 20 20 20
Pullman 82 52 82 54 81 51 / 20 10 10 20 20 20
Lewiston 88 61 90 62 87 61 / 20 10 10 20 20 20
Colville 83 52 86 55 86 52 / 40 10 10 30 20 30
Sandpoint 80 49 81 51 80 51 / 40 20 10 20 20 20
Kellogg 79 53 83 55 81 54 / 20 10 10 20 20 20
Moses Lake 85 58 83 60 82 57 / 30 10 10 30 20 20
Wenatchee 85 60 82 62 80 59 / 40 10 20 20 20 20
Omak 83 57 84 59 85 57 / 40 10 20 20 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 2 PM PDT this afternoon for Northern and
Central Idaho Panhandle (Zone 101).
WA...Red Flag Warning until 2 PM PDT this afternoon for East
Washington Northeast (Zone 686)-East Washington Northern
Columbia Basin (Zone 673)-East Washington Okanogan
Highlands (Zone 687)-East Washington Palouse and Spokane
Area (Zone 674).
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT FRI AUG 23 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM CDT FRI AUG 23 2013
MAIN SHORT TERM CONCERN IS SHOWER/THUNDERSTORM CHANCES.
WATER VAPOR/RAP 500MB ANALYSIS THIS AFTERNOON SHOWING A PERSISTENT
DEEP TROUGHS OF LOW PRESSURE ALONG THE WEST AND EAST COASTS WHILE
AMPLIFYING RIDGE WAS BUDGING SLOWLY FROM THE INTERMOUNTAIN WEST INTO
THE CENTRAL CONUS. AT THE SURFACE...HIGH PRESSURE WAS CENTERED OVER
THE GREAT LAKES REGION. INCREASING SOUTH/SOUTHEAST FLOW WAS NOTED
ACROSS OUR AREA ON THE BACKSIDE OF THE HIGH WITH TEMPERATURES IN THE
UPPER 70S TO LOWER 80S.
CURRENTLY WATCHING WATER VAPOR CLOSELY GIVEN MONSOONAL FLOW TAP INTO
THE INTERMOUNTAIN WEST WITH EMBEDDED SHORTWAVE TROUGH/MCV ACTIVITY.
ONE SUCH WAVE WAS NOTED MOVING OUT OF WY INTO SD AT THIS TIME. THIS
WAVE IS EXPECTED TO PROPAGATE EASTWARD TO THE AREA LATE TONIGHT INTO
SATURDAY AND INTERACT WITH AN APPROACHING WARM FRONT. ALSO OF NOTE
WILL BE EASTERN PERIPHERY OF INCREASING ISENTROPIC LIFT AND MOISTURE
TRANSPORT IMPINGING ON THE AREA. BOTTOM LINE WILL BE INCREASING
MID-LEVEL CLOUD COVER ALONG WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS MAINLY WEST OF THE MISSISSIPPI RIVER AFTER MIDNIGHT...
AND THEN ACROSS THE REST OF THE AREA SATURDAY. NAM HAS MLCAPE VALUES
IN THE 1000-1500J/KG RANGE ACROSS WESTERN WI INTO SOUTHEAST
MN/NORTHEAST IA WITH 1-6KM BULK SHEAR VALUES IN THE 20-25KT RANGE.
GIVEN THIS FACT...WILL HAVE TO WATCH FOR AN ISOLATED VIGOROUS STORM
WITH HEAVIER DOWNPOUR/SMALL HAIL THREAT. OTHERWISE...LOWS
TONIGHT ARE EXPECTED TO BOTTOM OUT IN THE UPPER 50S TO THE MIDDLE
60S WITH HIGHS SATURDAY IN THE 80-85 DEGREE RANGE.
APPEARS BULK OF SHOWER/THUNDERSTORM ACTIVITY SHOULD PUSH NORTHEAST
OF THE AREA WIT THE PASSAGE OF THE WARM FRONT. HOWEVER...MOISTURE
TRANSPORT VECTORS STILL FOCUS ACROSS PORTION OF THE AREA MAINLY
NORTH OF I-94 THROUGH THE NIGHT. AS SUCH...KEPT A 20-30 PERCENT
PROBABILITY OF SHOWERS/THUNDERSTORMS ACROSS THAT AREA. WITH
INCREASING HUMIDITY AND GETTING INTO THE WARM SECTOR...LOWS SATURDAY
NIGHT EXPECTED TO BOTTOM OUT IN THE UPPER 60S TO LOWER 70S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM CDT FRI AUG 23 2013
MAIN TOPIC OF CONCERN THROUGH THE LONG TERM PERIOD WILL BE
INCREASING HEAT WITH BUILDING MID/UPPER LEVEL RIDGE OVER THE CENTRAL
CONUS AND UPPER MISSISSIPPI RIVER VALLEY REGION. HOWEVER...MAY SEE A
COUPLE WEAK TROUGH PASSAGES WITH SHOWER/THUNDERSTORM CHANCES. AS A
RESULT...NOT OVERLY CONFIDENT ON HEAT HAZARD HEADLINE AREA PLACEMENT
AT THIS TIME. IT APPEARS AT THIS TIME...THE HIGHEST LIKELIHOOD FOR
HEAT HAZARD HEADLINES WOULD BE FROM I-94 AND SOUTH...WHICH IS
ENTRENCHED MORE INTO THE RIDGE. AREAS NORTH AND EAST OF THIS WILL BE
SUSCEPTIBLE TO THESE WEAK TROUGH PASSAGES AND POTENTIAL FOR
THUNDERSTORM COMPLEXES ROLLING THROUGH. IT APPEARS HEAT INDEX
CRITERIA FOR HEADLINES //100 DEGREES +// WILL BE MET MONDAY AND
TUESDAY AFTERNOONS AND EARLY EVENINGS. AS A RESULT...WILL PROBABLY
HOLD OFF ON ANY HEAT HEADLINE ISSUANCE FOR NOW.
TEMPERATURE/HEAT DETAILS...
ECMWF AND GFS BEGIN TO HEAT THINGS UP ON SUNDAY. GOOD
MIXING/SOUTHWEST BREEZE WILL COMBINE WITH 925 TEMPERATURES IN THE
27-29C RANGE FOR HIGHS IN THE 90-95F DEGREE RANGE. GOOD MIXING
SHOULD DECREASE HUMIDITY SOMEWHAT WITH HEAT INDICES TOPPING OFF IN
THE 95-100 DEGREE RANGE.
HIGHER HUMIDITY WITH TEMPERATURES TOPPING OFF IN THE LOWER/MIDDLE
90S MONDAY AND TUESDAY WILL PUSH HEAT INDICES INTO THE 100-105
DEGREE RANGE...ESPECIALLY SOUTHWEST OF I-94. THESE DAYS WILL NEED AT
LEAST A HEAT ADVISORY.
WEDNESDAY/THURSDAY/FRIDAY LOOKING A BIT MORE UNCERTAIN WITH THE
23.12Z ECMWF/GFS SHOWING COOLING 925MB TEMPERATURES WITH TROUGH
PASSAGE THROUGH PARTS OF THE AREA/GREAT LAKES REGION. THIS WOULD
KEEP THE AREA BELOW HEAT ADVISORY CRITERIA WITH THE POSSIBLE
EXCEPTION OF NORTHEAST IA INTO FAR SOUTHWEST WI WEDNESDAY AFTERNOON.
MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 600 PM CDT FRI AUG 23 2013
A WARM FRONT WILL GRADUALLY LIFT NORTHEAST ACROSS THE REGION LATER
TONIGHT/EARLY SAT. NOT A BIG SHIFT IN THE WINDS...AND NOT MUCH
CONVERGENCE AROUND IT. HOWEVER...MESO MODELS POINT TO SOME LOW LEVEL
WARM AIR/ISENTROPIC CONVERGENCE WITH IT...ALTHOUGH NOT A WHOLE LOT
OF SATURATION THROUGH THE COLUMN PER BUFKIT SOUNDINGS. SEE SOME
SCT-BKN CLOUDS...BUT NOT MUCH IN THE WAY OF PCPN AT THIS TIME. THAT
SAID...THE HRRR SUGGESTS A THIN LINE OF SCT-BKN -SHRA COULD TRACK
ACROSS KLSE NEAR 12Z. OVERALL...THINK THE BETTER CHANCES FOR
KRST/KLSE WILL COME LATER IN THE DAY SAT/SAT NIGHT...AS THE TAF
SITES GET UNDER STRONGER SOUTHERLY FLOW. BULK OF THE MOISTURE
TRANSPORT SHIFTS NORTH BY THE THEN THOUGH...AS DOES THE STRONGEST
THERMODYNAMICS. PLUS...WITH AMPLE LOW LEVEL WARM AIR COMES A
CAP...SERVING TO INHIBIT CONVECTION. BEST SHRA/TS WILL LIKELY HOLD
NORTH OF KRST/KLSE THROUGH SAT NIGHT AS A RESULT.
HIGH PRESSURE EXITS EAST TONIGHT...WITH A TIGHTENING PRESSURE
GRADIENT WORKING IN OVERNIGHT. SFC WINDS SHOULD NOT LIGHTEN UP TOO
MUCH AS A RESULT...WITH BUFKIT SOUNDINGS INDICATING GOOD STIRRING BY
200 FT. THUS...WINDS WILL BE THE MAIN LIMITING FACTOR TO ANY FOG
POTENTIAL. EXPECT HIGHER GUSTS SAT AFTERNOON AS WINDS BEGIN TO MIX.
&&
.CLIMATE...
ISSUED AT 307 PM CDT FRI AUG 23 2013
HERE ARE SOME RECORD HIGHS FOR LA CROSSE AND ROCHESTER THROUGH LABOR
DAY WEEKEND GIVEN THE UPCOMING INCREASE IN HEAT. FOR MORE CLIMATE
INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
CLIMATE......DAS/AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1220 PM CDT FRI AUG 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 258 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN IN THE SHORT TERM IS ON PRECIPITATION CHANCES
TONIGHT.
CURRENTLY AS OF 07Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
JUST OFF THE WEST COAST OF THE U.S....RIDGING COVERING MUCH OF THE
PLAINS...AND TROUGHING IN SOUTHEAST CANADA. VARIOUS MONSOONAL
RELATED SHORTWAVES WERE ROTATING AROUND THE UPPER RIDGE ACROSS THE
U.S. ROCKIES...WITH THE MAIN SYNOPTIC SHORTWAVE OF NOTE OVER
OREGON. THE FORECAST AREA LIES IN THE INFLECTION OF THE RIDGE AND
TROUGH...RESULTING IN SUBSIDENCE AND DRYING. THIS IS REFLECTED
WELL BY HIGH PRESSURE THAT IS CENTERED OVER UPPER MICHIGAN...ALONG
WITH 00Z RAOBS FROM MPX AND GRB WHICH HAD PRECIPITABLE WATER
VALUES OF 0.94 AND 0.81 RESPECTIVELY. THESE VALUES ARE MUCH LOWER
THAN THE 1.8-2 INCH VALUES THAT WERE PRESENT ALONG/SOUTH OF I-90
AT 12Z YESTERDAY WITH THE MCS THAT ROLLED THROUGH. LIGHT WINDS
ASSOCIATED WITH THE HIGH...GOOD RADIATIONAL COOLING
CONDITIONS...RECENT RAIN AND SURFACE DEWPOINTS WHICH CLIMBED FROM
EVENING EVAPOTRANSPORATION HAS LED TO SOME FOG. THE THICKEST FOG
IS OVER NORTHEAST IA AND FAR SOUTHWEST WI WHERE A DENSE FOG
ADVISORY WAS JUST ISSUED. AIRMASS OVER THE FORECAST AREA REMAINS
RELATIVELY WARM WITH 850MB READINGS OF 14-16C...WHICH ARE NORMAL.
HOWEVER...TO THE WEST...MUCH WARMER 850MB TEMPS OF 20-25C HAVE
SPREAD NORTH FROM THE CENTRAL PLAINS INTO MONTANA.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT PUSHING THE UPPER RIDGE GRADUALLY
EASTWARD DURING THE NEXT 24 HOURS...SUCH THAT AT 12Z SATURDAY THE
RIDGE AXIS EXTENDS INTO MINNESOTA WITH THE SUBTROPICAL HIGH CENTERED
OVER KANSAS AND MISSOURI. THE BIGGEST CONCERN IS ON THE MONSOONAL
SHORTWAVES ROTATING AROUND THE RIDGE. ONE SUCH SHORTWAVE MODELS
SUGGEST COMING ACROSS THE DAKOTAS INTO WESTERN MINNESOTA
TONIGHT...WHICH COULD TRY TO SPREAD SOME PRECIP EAST TOWARDS THE
FORECAST AREA.
DETAILS...
QUIET CONDITIONS TODAY WITH THE FORECAST AREA UNDER THE INFLUENCE OF
THE HIGH PRESSURE AREA OVER UPPER MICHIGAN. NOTE THAT THE HIGH DOES
START DRIFTING OFF TO THE EAST...WHICH IN TURN DEVELOPS A RETURN
SOUTHERLY FLOW OVER THE FORECAST AREA. THIS RETURN FLOW HELPS TO
DEFLECT THE BRIEF COOLING THE HIGH BRINGS IN THIS MORNING...CAUSING
HIGH TEMPERATURES TODAY TO END UP SIMILAR TO YESTERDAY. NOTE ANY FOG
SHOULD MIX OUT QUICKLY BETWEEN 9-10 AM.
HEADING INTO TONIGHT...AS THE SHORTWAVE COMES INTO THE DAKOTAS...
DPVA ASSOCIATED WITH IT LOOKS TO INTERACT WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. 850MB MOISTURE TRANSPORT PROGS FROM
THE 23.00Z NAM/GFS/REGIONAL CANADIAN AND ECMWF ALL POINT TO
CONVECTION BREAKING OUT ACROSS EASTERN SOUTH DAKOTA THIS EVENING...
ON THE NOSE OF ENHANCED MOISTURE TRANSPORT WITHIN THE LOW LEVEL JET.
THIS CONVECTION THEN TRANSLATES EAST. MODEL CONSENSUS WOULD SUGGEST
THE BULK OF THE CONVECTION STAYS WEST OF THE AREA PRIOR TO 12Z
SATURDAY...BUT DID INCLUDE A 20-30 PERCENT CHANCE OVER WESTERN
PORTIONS OF THE FORECAST AREA IN THE EVENT SOME STORMS FORM ON THE
EASTERN EDGE OF THE MOISTURE TRANSPORT AS INDICATED BY THE 23.00Z
NAM. COMBINATION OF INCREASING MID CLOUDS WITH THE MOISTURE
TRANSPORT...AS WELL AS SURFACE WINDS...WILL RESULT IN A WARMER
NIGHT. A BLEND OF MODEL GUIDANCE LOOKS REASONABLE FOR LOWS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 258 AM CDT FRI AUG 23 2013
HAZARDS...
THE BIG ONE HERE IS HEAT. A LONG DURATION HEAT EVENT APPEARS
LIKELY...BEGINNING ON SUNDAY AND MOSTLY LASTING THROUGH THE REST OF
THE LONG TERM PERIOD AND BEYOND. HOWEVER...WEDNESDAY AND THURSDAY
ARE MOST PROBLEMATIC AND HAVE PRECLUDED ISSUING ANY HEAT HAZARDS AT
THIS TIME. SOME HEAT HAZARDS WILL BE NEEDED EVENTUALLY... ESPECIALLY
FOR MONDAY AND TUESDAY.
SYNOPTIC OVERVIEW...
23.00Z ECMWF/GFS/CANADIAN AND THE PORTION OF THE NAM THROUGH 84
HOURS ARE ALL IN GOOD AGREEMENT THAT THE UPPER PATTERN CHANGES VERY
LITTLE FROM WHERE IT ENDS UP AT 12Z SATURDAY THROUGH THE ENTIRE LONG
TERM PERIOD. THE UPPER RIDGE AXIS APPEARS TO STAY CENTERED OVER
MINNESOTA WHILE THE SUBTROPICAL HIGH CENTER STRENGTHENS OVER KANSAS
AND MISSOURI DURING THE WEEKEND. VARIOUS SHORTWAVES OF MONSOONAL
ORIGIN AND ENHANCED BY CONVECTION WILL ROTATE AROUND THE RIDGE...
MOST OF WHICH APPEAR TO TAKE A TRACK THROUGH THE DAKOTAS...NORTHERN
MINNESOTA AND THROUGH MICHIGAN AND NORTHERN WISCONSIN. THIS IS A
PATTERN MORE TYPICAL OF JULY OR EARLY AUGUST VERSUS LATE AUGUST. THE
BIG FORECAST QUESTION FROM THE PRECIPITATION SIDE OF THINGS WILL BE
DOES ANY CONVECTION ASSOCIATED WITH THE SHORTWAVES DROP SOUTH INTO
THE FORECAST AREA. OTHERWISE...ITS ALL ABOUT HOW HOT IT WILL BE.
PRECIPITATION DETAILS...
FOR SATURDAY...ALTHOUGH ALL INDICATIONS ARE THAT THE NOSE OF THE
850MB MOISTURE TRANSPORT WILL SHIFT NORTH UP INTO NORTHWEST
ONTARIO...THE FORECAST AREA SITS ON THE EASTERN EDGE OF THE
MOISTURE TRANSPORT. THE NAM...GFS...ECMWF AND REGIONAL CANADIAN
ALL DEVELOP SCATTERED CONVECTION THROUGHOUT THE DAY...DUE TO THE
COMBINATION OF THIS MOISTURE TRANSPORT AND ELEVATED INSTABILITY
ROOTED AT OR ABOVE 900MB. ADDITIONALLY...WE HAVE THAT SHORTWAVE
COMING FROM THE DAKOTAS TO PROVIDE SOME DPVA HELP. THEREFORE...
HAVE 20-40 PERCENT CHANCES IN THE FORECAST. 1-6KM SHEAR VALUES OF
20-25 KT SHOULD PRECLUDE ANY ORGANIZED SEVERE THREAT...THOUGH
INCREASING PRECIPITABLE WATER VALUES SUGGEST POTENTIAL FOR SOME
LOCALLY HEAVY RAIN.
PRECIPITATION CHANCES SHOULD BEGIN TO SHIFT NORTH SATURDAY NIGHT
WITH THE SHORTWAVE PASSED...THE NOSE OF THE 850MB MOISTURE TRANSPORT
CENTERED FROM NORTHWEST ONTARIO INTO UPPER MI AND THE FORECAST AREA
BECOMING MORE UNDER THE MOISTURE TRANSPORT STREAM ITSELF. THE 23.00Z
GFS IS AN OUTLIER HAVING CONVECTION ALL THE WAY SOUTH TOWARDS
DUBUQUE WHEREAS ALL OTHER GUIDANCE SUGGESTS ALONG/NORTH I-94 OR EVEN
NORTH OF THE FORECAST AREA. LEANED AWAY FROM THE GFS...WHICH STAYS
IN GOOD CONTINUITY WITH THE PREVIOUS FORECAST. HIGH CONFIDENCE THAT
CONVECTION WILL STAY WELL OFF TO THE NORTHEAST SUNDAY. ANOTHER
MONSOON-RELATED SHORTWAVE IS SUGGESTED BY SOME MODELS TO COME ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT. THE AIRMASS MAY
BE CAPPED OFF EVEN TO ELEVATED CONVECTION...BUT WITH THE 22.12Z
ECMWF AND 23.00Z GFS DEPICTING SOME CONVECTION WITH THE SHORTWAVE...
FELT A 20-30 PERCENT CHANCE IS NEEDED. 23.00Z ECMWF IS DRY FOR
SUNDAY NIGHT...WHICH MAY TURN OUT IN REALITY. FOR MONDAY AND
BEYOND...MODELS OCCASIONALLY PRODUCE CONVECTION...PARTICULARLY
ALONG AND NORTH AND EAST OF I-94 AS SHORTWAVES ROUND THE RIDGE.
FROM A CONSENSUS STANDPOINT...THIS YIELDS 20-30 PERCENT CHANCES
NEEDED EACH DAY IN THIS AREA.
TEMPERATURE DETAILS...
FOR SATURDAY...BETWEEN THE CONVECTION AROUND AS WELL AS INDICATIONS
OF PLENTY OF CIRRUS...TEMPERATURES ARE LIKELY NOT TO REACH THEIR
MAXIMUM POTENTIAL. 850MB TEMPS CLIMBING TO 16C EAST TO 19C WEST
WOULD SUPPORT HIGHS IN THE MID TO PERHAPS UPPER 80S...BUT THE
AFOREMENTIONED ISSUES LIKELY TO HOLD HIGH TEMPS 5-10 DEGREES COOLER.
TEMPERATURES REALLY BEGIN TO HEAT UP ON SUNDAY. COMBINATION OF 925MB
TEMPS CLIMBING TO 26-28C AND A BREEZY SOUTHWEST WIND SHOULD EASILY
PROPEL HIGHS INTO THE UPPER 80S TO LOW 90S. THE WINDS ARE ALSO GOING
TO ADVECT IN HIGHER DEWPOINTS...LIKELY IN THE UPPER 60S TO LOW 70S.
HEAT INDICES AS A RESULT TOP OUT IN THE 95 TO 100 RANGE.
MONDAY AND TUESDAY BOTH LOOK HOT AS THE WARM AIR SHIFTS EAST OVER
THE FORECAST AREA. 925MB TEMPS RISE FURTHER TO 27-29C...PERHAPS EVEN
30C. WITH PLENTY OF SUN...ESPECIALLY SOUTHWEST OF I-94...HIGHS OF
90-95 SHOULD OCCUR. DEWPOINTS MAY NOT CHANGE MUCH COMPARED TO
SUNDAY...CAUSING HEAT INDICES TO LIKELY JUMP TO 100-105. THESE
DAYS WILL NEED AT LEAST A HEAT ADVISORY.
WEDNESDAY AND THURSDAY BECAME A BIT MORE UNCERTAIN WITH THE 23.00Z
ECMWF/UKMET. THEY HAVE A SHORTWAVE TROUGH DIGGING INTO NEW ENGLAND
WHICH ALLOWS A BACK DOOR COLD FRONT TO COME THROUGH THE FORECAST
AREA. 925MB TEMPS COOL TO 24-26C...WHICH WOULD KEEP HIGHS PERHAPS
EVEN BELOW 90. ON THE OTHER HAND...THE 23.00Z GFS DOESNT DROP THE
COLD FRONT THROUGH...KEEPING 925MB TEMPS UP BETWEEN 28-32C. FOR
NOW FOLLOWED A CONSENSUS...WHICH RESULTS IN THESE DAYS BELOW HEAT
ADVISORY CONDITIONS.
LOWS WILL STAY QUITE WARM DURING THIS STRETCH...LIKELY IN THE LOW
TO MID 70S EVERY NIGHT.
GIVEN THE UNCERTAINTY WITH WEDNESDAY AND THURSDAY...AND THE VERY
MARGINAL CONDITIONS ON SUNDAY...HAVE NOT ISSUED ANY HEAT HAZARDS
AT THIS TIME.
NOTE THAT MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM CDT FRI AUG 23 2013
RESIDUAL LOWER LEVEL MOISTURE TRAPPED UNDER A SHALLOW INVERSION
CONTINUES TO IMPACT THE TAF SITES EARLY THIS AFTERNOON WITH SCT-BKN
MVFR CLOUDS/CIGS. DIURNAL WARMING/MIXING IS GRADUALLY RAISING THE
CLOUD/CIG HGTS...BUT DISTANCE-SPEED TOOL AND WEAK LOW LEVEL WINDS
SHOWS THIS MOISTURE/CLOUDS TO CONTINUE IMPACTING THE TAF SITES INTO
MID AFTERNOON. HAVE ADDED SOME SCT-BKN CU/STRATO-CU DECKS TO TAFS
THRU 20Z. GOOD VFR THEN EXPECTED LATER THIS AFTERNOON/EVENING AS
THESE CLOUDS/MOISTURE MOVE NORTH OF THE TAF SITES. SOME MVFR VSBYS
IN HZ/BR EXPECTED LATER TONIGHT...WITH SOUTH TO SOUTHEAST GRADIENT
WINDS KEEPING BOUNDARY LAYER STIRRED ENOUGH TO KEEP LATE NIGHT/EARLY
MORNING IFR VSBYS IN BR/FG ISOLATED.
A WARM FRONT AND INCREASING MOISTURE/LIFT IN THE 850-700MB LAYER
SPREADS NORTHEAST ACROSS THE AREA LATER TONIGHT/SAT. WIDELY SCT TO
SCT SHRA AND A FEW TSRA EXPECTED AS THIS FRONT/FORCING MOVE ACROSS
THE TAF SITES. LEFT THIS VCSH AT BOTH KRST/KLSE WITH BKN CIGS IN THE
4K-5K FT RANGE AS THE FRONT PASSES. ANY CLOUDS/CIGS BEHIND THE WARM
FRONT ON SAT SHOULD REMAIN ABOVE THE 4K-5K FT LEVEL.
&&
.CLIMATE...
ISSUED AT 343 AM CDT FRI AUG 23 2013
GIVEN THE UPCOMING STRETCH OF HEAT...HERE ARE SOME RECORD HIGHS FOR
LA CROSSE AND ROCHESTER THROUGH LABOR DAY WEEKEND. MORE CLIMATE
INFORMATION CAN BE FOUND ON OUR WEBSITE IN THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGHS ARE 78-80 AT LA CROSSE AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
CLIMATE......AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
657 AM CDT FRI AUG 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 258 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN IN THE SHORT TERM IS ON PRECIPITATION CHANCES
TONIGHT.
CURRENTLY AS OF 07Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
JUST OFF THE WEST COAST OF THE U.S....RIDGING COVERING MUCH OF THE
PLAINS...AND TROUGHING IN SOUTHEAST CANADA. VARIOUS MONSOONAL
RELATED SHORTWAVES WERE ROTATING AROUND THE UPPER RIDGE ACROSS THE
U.S. ROCKIES...WITH THE MAIN SYNOPTIC SHORTWAVE OF NOTE OVER
OREGON. THE FORECAST AREA LIES IN THE INFLECTION OF THE RIDGE AND
TROUGH...RESULTING IN SUBSIDENCE AND DRYING. THIS IS REFLECTED
WELL BY HIGH PRESSURE THAT IS CENTERED OVER UPPER MICHIGAN...ALONG
WITH 00Z RAOBS FROM MPX AND GRB WHICH HAD PRECIPITABLE WATER
VALUES OF 0.94 AND 0.81 RESPECTIVELY. THESE VALUES ARE MUCH LOWER
THAN THE 1.8-2 INCH VALUES THAT WERE PRESENT ALONG/SOUTH OF I-90
AT 12Z YESTERDAY WITH THE MCS THAT ROLLED THROUGH. LIGHT WINDS
ASSOCIATED WITH THE HIGH...GOOD RADIATIONAL COOLING
CONDITIONS...RECENT RAIN AND SURFACE DEWPOINTS WHICH CLIMBED FROM
EVENING EVAPOTRANSPORATION HAS LED TO SOME FOG. THE THICKEST FOG
IS OVER NORTHEAST IA AND FAR SOUTHWEST WI WHERE A DENSE FOG
ADVISORY WAS JUST ISSUED. AIRMASS OVER THE FORECAST AREA REMAINS
RELATIVELY WARM WITH 850MB READINGS OF 14-16C...WHICH ARE NORMAL.
HOWEVER...TO THE WEST...MUCH WARMER 850MB TEMPS OF 20-25C HAVE
SPREAD NORTH FROM THE CENTRAL PLAINS INTO MONTANA.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT PUSHING THE UPPER RIDGE GRADUALLY
EASTWARD DURING THE NEXT 24 HOURS...SUCH THAT AT 12Z SATURDAY THE
RIDGE AXIS EXTENDS INTO MINNESOTA WITH THE SUBTROPICAL HIGH CENTERED
OVER KANSAS AND MISSOURI. THE BIGGEST CONCERN IS ON THE MONSOONAL
SHORTWAVES ROTATING AROUND THE RIDGE. ONE SUCH SHORTWAVE MODELS
SUGGEST COMING ACROSS THE DAKOTAS INTO WESTERN MINNESOTA
TONIGHT...WHICH COULD TRY TO SPREAD SOME PRECIP EAST TOWARDS THE
FORECAST AREA.
DETAILS...
QUIET CONDITIONS TODAY WITH THE FORECAST AREA UNDER THE INFLUENCE OF
THE HIGH PRESSURE AREA OVER UPPER MICHIGAN. NOTE THAT THE HIGH DOES
START DRIFTING OFF TO THE EAST...WHICH IN TURN DEVELOPS A RETURN
SOUTHERLY FLOW OVER THE FORECAST AREA. THIS RETURN FLOW HELPS TO
DEFLECT THE BRIEF COOLING THE HIGH BRINGS IN THIS MORNING...CAUSING
HIGH TEMPERATURES TODAY TO END UP SIMILAR TO YESTERDAY. NOTE ANY FOG
SHOULD MIX OUT QUICKLY BETWEEN 9-10 AM.
HEADING INTO TONIGHT...AS THE SHORTWAVE COMES INTO THE DAKOTAS...
DPVA ASSOCIATED WITH IT LOOKS TO INTERACT WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. 850MB MOISTURE TRANSPORT PROGS FROM
THE 23.00Z NAM/GFS/REGIONAL CANADIAN AND ECMWF ALL POINT TO
CONVECTION BREAKING OUT ACROSS EASTERN SOUTH DAKOTA THIS EVENING...
ON THE NOSE OF ENHANCED MOISTURE TRANSPORT WITHIN THE LOW LEVEL JET.
THIS CONVECTION THEN TRANSLATES EAST. MODEL CONSENSUS WOULD SUGGEST
THE BULK OF THE CONVECTION STAYS WEST OF THE AREA PRIOR TO 12Z
SATURDAY...BUT DID INCLUDE A 20-30 PERCENT CHANCE OVER WESTERN
PORTIONS OF THE FORECAST AREA IN THE EVENT SOME STORMS FORM ON THE
EASTERN EDGE OF THE MOISTURE TRANSPORT AS INDICATED BY THE 23.00Z
NAM. COMBINATION OF INCREASING MID CLOUDS WITH THE MOISTURE
TRANSPORT...AS WELL AS SURFACE WINDS...WILL RESULT IN A WARMER
NIGHT. A BLEND OF MODEL GUIDANCE LOOKS REASONABLE FOR LOWS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 258 AM CDT FRI AUG 23 2013
HAZARDS...
THE BIG ONE HERE IS HEAT. A LONG DURATION HEAT EVENT APPEARS
LIKELY...BEGINNING ON SUNDAY AND MOSTLY LASTING THROUGH THE REST OF
THE LONG TERM PERIOD AND BEYOND. HOWEVER...WEDNESDAY AND THURSDAY
ARE MOST PROBLEMATIC AND HAVE PRECLUDED ISSUING ANY HEAT HAZARDS AT
THIS TIME. SOME HEAT HAZARDS WILL BE NEEDED EVENTUALLY... ESPECIALLY
FOR MONDAY AND TUESDAY.
SYNOPTIC OVERVIEW...
23.00Z ECMWF/GFS/CANADIAN AND THE PORTION OF THE NAM THROUGH 84
HOURS ARE ALL IN GOOD AGREEMENT THAT THE UPPER PATTERN CHANGES VERY
LITTLE FROM WHERE IT ENDS UP AT 12Z SATURDAY THROUGH THE ENTIRE LONG
TERM PERIOD. THE UPPER RIDGE AXIS APPEARS TO STAY CENTERED OVER
MINNESOTA WHILE THE SUBTROPICAL HIGH CENTER STRENGTHENS OVER KANSAS
AND MISSOURI DURING THE WEEKEND. VARIOUS SHORTWAVES OF MONSOONAL
ORIGIN AND ENHANCED BY CONVECTION WILL ROTATE AROUND THE RIDGE...
MOST OF WHICH APPEAR TO TAKE A TRACK THROUGH THE DAKOTAS...NORTHERN
MINNESOTA AND THROUGH MICHIGAN AND NORTHERN WISCONSIN. THIS IS A
PATTERN MORE TYPICAL OF JULY OR EARLY AUGUST VERSUS LATE AUGUST. THE
BIG FORECAST QUESTION FROM THE PRECIPITATION SIDE OF THINGS WILL BE
DOES ANY CONVECTION ASSOCIATED WITH THE SHORTWAVES DROP SOUTH INTO
THE FORECAST AREA. OTHERWISE...ITS ALL ABOUT HOW HOT IT WILL BE.
PRECIPITATION DETAILS...
FOR SATURDAY...ALTHOUGH ALL INDICATIONS ARE THAT THE NOSE OF THE
850MB MOISTURE TRANSPORT WILL SHIFT NORTH UP INTO NORTHWEST
ONTARIO...THE FORECAST AREA SITS ON THE EASTERN EDGE OF THE
MOISTURE TRANSPORT. THE NAM...GFS...ECMWF AND REGIONAL CANADIAN
ALL DEVELOP SCATTERED CONVECTION THROUGHOUT THE DAY...DUE TO THE
COMBINATION OF THIS MOISTURE TRANSPORT AND ELEVATED INSTABILITY
ROOTED AT OR ABOVE 900MB. ADDITIONALLY...WE HAVE THAT SHORTWAVE
COMING FROM THE DAKOTAS TO PROVIDE SOME DPVA HELP. THEREFORE...
HAVE 20-40 PERCENT CHANCES IN THE FORECAST. 1-6KM SHEAR VALUES OF
20-25 KT SHOULD PRECLUDE ANY ORGANIZED SEVERE THREAT...THOUGH
INCREASING PRECIPITABLE WATER VALUES SUGGEST POTENTIAL FOR SOME
LOCALLY HEAVY RAIN.
PRECIPITATION CHANCES SHOULD BEGIN TO SHIFT NORTH SATURDAY NIGHT
WITH THE SHORTWAVE PASSED...THE NOSE OF THE 850MB MOISTURE TRANSPORT
CENTERED FROM NORTHWEST ONTARIO INTO UPPER MI AND THE FORECAST AREA
BECOMING MORE UNDER THE MOISTURE TRANSPORT STREAM ITSELF. THE 23.00Z
GFS IS AN OUTLIER HAVING CONVECTION ALL THE WAY SOUTH TOWARDS
DUBUQUE WHEREAS ALL OTHER GUIDANCE SUGGESTS ALONG/NORTH I-94 OR EVEN
NORTH OF THE FORECAST AREA. LEANED AWAY FROM THE GFS...WHICH STAYS
IN GOOD CONTINUITY WITH THE PREVIOUS FORECAST. HIGH CONFIDENCE THAT
CONVECTION WILL STAY WELL OFF TO THE NORTHEAST SUNDAY. ANOTHER
MONSOON-RELATED SHORTWAVE IS SUGGESTED BY SOME MODELS TO COME ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT. THE AIRMASS MAY
BE CAPPED OFF EVEN TO ELEVATED CONVECTION...BUT WITH THE 22.12Z
ECMWF AND 23.00Z GFS DEPICTING SOME CONVECTION WITH THE SHORTWAVE...
FELT A 20-30 PERCENT CHANCE IS NEEDED. 23.00Z ECMWF IS DRY FOR
SUNDAY NIGHT...WHICH MAY TURN OUT IN REALITY. FOR MONDAY AND
BEYOND...MODELS OCCASIONALLY PRODUCE CONVECTION...PARTICULARLY
ALONG AND NORTH AND EAST OF I-94 AS SHORTWAVES ROUND THE RIDGE.
FROM A CONSENSUS STANDPOINT...THIS YIELDS 20-30 PERCENT CHANCES
NEEDED EACH DAY IN THIS AREA.
TEMPERATURE DETAILS...
FOR SATURDAY...BETWEEN THE CONVECTION AROUND AS WELL AS INDICATIONS
OF PLENTY OF CIRRUS...TEMPERATURES ARE LIKELY NOT TO REACH THEIR
MAXIMUM POTENTIAL. 850MB TEMPS CLIMBING TO 16C EAST TO 19C WEST
WOULD SUPPORT HIGHS IN THE MID TO PERHAPS UPPER 80S...BUT THE
AFOREMENTIONED ISSUES LIKELY TO HOLD HIGH TEMPS 5-10 DEGREES COOLER.
TEMPERATURES REALLY BEGIN TO HEAT UP ON SUNDAY. COMBINATION OF 925MB
TEMPS CLIMBING TO 26-28C AND A BREEZY SOUTHWEST WIND SHOULD EASILY
PROPEL HIGHS INTO THE UPPER 80S TO LOW 90S. THE WINDS ARE ALSO GOING
TO ADVECT IN HIGHER DEWPOINTS...LIKELY IN THE UPPER 60S TO LOW 70S.
HEAT INDICES AS A RESULT TOP OUT IN THE 95 TO 100 RANGE.
MONDAY AND TUESDAY BOTH LOOK HOT AS THE WARM AIR SHIFTS EAST OVER
THE FORECAST AREA. 925MB TEMPS RISE FURTHER TO 27-29C...PERHAPS EVEN
30C. WITH PLENTY OF SUN...ESPECIALLY SOUTHWEST OF I-94...HIGHS OF
90-95 SHOULD OCCUR. DEWPOINTS MAY NOT CHANGE MUCH COMPARED TO
SUNDAY...CAUSING HEAT INDICES TO LIKELY JUMP TO 100-105. THESE
DAYS WILL NEED AT LEAST A HEAT ADVISORY.
WEDNESDAY AND THURSDAY BECAME A BIT MORE UNCERTAIN WITH THE 23.00Z
ECMWF/UKMET. THEY HAVE A SHORTWAVE TROUGH DIGGING INTO NEW ENGLAND
WHICH ALLOWS A BACK DOOR COLD FRONT TO COME THROUGH THE FORECAST
AREA. 925MB TEMPS COOL TO 24-26C...WHICH WOULD KEEP HIGHS PERHAPS
EVEN BELOW 90. ON THE OTHER HAND...THE 23.00Z GFS DOESNT DROP THE
COLD FRONT THROUGH...KEEPING 925MB TEMPS UP BETWEEN 28-32C. FOR
NOW FOLLOWED A CONSENSUS...WHICH RESULTS IN THESE DAYS BELOW HEAT
ADVISORY CONDITIONS.
LOWS WILL STAY QUITE WARM DURING THIS STRETCH...LIKELY IN THE LOW
TO MID 70S EVERY NIGHT.
GIVEN THE UNCERTAINTY WITH WEDNESDAY AND THURSDAY...AND THE VERY
MARGINAL CONDITIONS ON SUNDAY...HAVE NOT ISSUED ANY HEAT HAZARDS
AT THIS TIME.
NOTE THAT MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 654 AM CDT FRI AUG 23 2013
THE COMBINATION OF LIGHT WINDS AND CLEAR SKIES RESULTED IN THE
DEVELOPMENT OF VALLEY FOG OVERNIGHT. AS HAS BEEN THE CASE DURING
THE PAST WEEK...THE RECENT DRYNESS HAS BEEN CAUSING WIDE RANGING
VISIBILITIES IN VALLEY AS IT MEANDERS THROUGH RIVER CHANNLE. KLSE
HAS RANGED FROM LITTLE AS A HALF MILE TO NOW 8 MILES...SO
CONFIDENCE IS ABOUT 60 PERCENT THAT A QUARTER MILE OR LESS WILL
MAKE IT BACK OVER THE AIR FIELD. BASED ON THE TIME OF
YEAR...EXPECT THAT THIS FOG WILL DISSIPATE RAPIDLY BETWEEN 23.14Z
AND 23.15Z.
FOR LATE TONIGHT...EXPECT A 4-5K DECK OF CLOUDS TO MOVE INTO THE
AREA AFTER 24.06Z AS A WARM FRONT APPROACHES THE AREA FROM WESTERN
MINNESOTA AND WESTERN IOWA. A FEW SHOWERS AND THUNDERSTORMS MAY
AFFECT KRST AFTER 24.10Z. HOWEVER CONFIDENCE WAS TOO LOW TO
INCLUDE IN THE TAF AT THIS TIME.
&&
.CLIMATE...
ISSUED AT 343 AM CDT FRI AUG 23 2013
GIVEN THE UPCOMING STRETCH OF HEAT...HERE ARE SOME RECORD HIGHS FOR
LA CROSSE AND ROCHESTER THROUGH LABOR DAY WEEKEND. MORE CLIMATE
INFORMATION CAN BE FOUND ON OUR WEBSITE IN THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGHS ARE 78-80 AT LA CROSSE AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ054-055-
061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CDT FRI AUG 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 258 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN IN THE SHORT TERM IS ON PRECIPITATION CHANCES
TONIGHT.
CURRENTLY AS OF 07Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
JUST OFF THE WEST COAST OF THE U.S....RIDGING COVERING MUCH OF THE
PLAINS...AND TROUGHING IN SOUTHEAST CANADA. VARIOUS MONSOONAL
RELATED SHORTWAVES WERE ROTATING AROUND THE UPPER RIDGE ACROSS THE
U.S. ROCKIES...WITH THE MAIN SYNOPTIC SHORTWAVE OF NOTE OVER
OREGON. THE FORECAST AREA LIES IN THE INFLECTION OF THE RIDGE AND
TROUGH...RESULTING IN SUBSIDENCE AND DRYING. THIS IS REFLECTED
WELL BY HIGH PRESSURE THAT IS CENTERED OVER UPPER MICHIGAN...ALONG
WITH 00Z RAOBS FROM MPX AND GRB WHICH HAD PRECIPITABLE WATER
VALUES OF 0.94 AND 0.81 RESPECTIVELY. THESE VALUES ARE MUCH LOWER
THAN THE 1.8-2 INCH VALUES THAT WERE PRESENT ALONG/SOUTH OF I-90
AT 12Z YESTERDAY WITH THE MCS THAT ROLLED THROUGH. LIGHT WINDS
ASSOCIATED WITH THE HIGH...GOOD RADIATIONAL COOLING
CONDITIONS...RECENT RAIN AND SURFACE DEWPOINTS WHICH CLIMBED FROM
EVENING EVAPOTRANSPORATION HAS LED TO SOME FOG. THE THICKEST FOG
IS OVER NORTHEAST IA AND FAR SOUTHWEST WI WHERE A DENSE FOG
ADVISORY WAS JUST ISSUED. AIRMASS OVER THE FORECAST AREA REMAINS
RELATIVELY WARM WITH 850MB READINGS OF 14-16C...WHICH ARE NORMAL.
HOWEVER...TO THE WEST...MUCH WARMER 850MB TEMPS OF 20-25C HAVE
SPREAD NORTH FROM THE CENTRAL PLAINS INTO MONTANA.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT PUSHING THE UPPER RIDGE GRADUALLY
EASTWARD DURING THE NEXT 24 HOURS...SUCH THAT AT 12Z SATURDAY THE
RIDGE AXIS EXTENDS INTO MINNESOTA WITH THE SUBTROPICAL HIGH CENTERED
OVER KANSAS AND MISSOURI. THE BIGGEST CONCERN IS ON THE MONSOONAL
SHORTWAVES ROTATING AROUND THE RIDGE. ONE SUCH SHORTWAVE MODELS
SUGGEST COMING ACROSS THE DAKOTAS INTO WESTERN MINNESOTA
TONIGHT...WHICH COULD TRY TO SPREAD SOME PRECIP EAST TOWARDS THE
FORECAST AREA.
DETAILS...
QUIET CONDITIONS TODAY WITH THE FORECAST AREA UNDER THE INFLUENCE OF
THE HIGH PRESSURE AREA OVER UPPER MICHIGAN. NOTE THAT THE HIGH DOES
START DRIFTING OFF TO THE EAST...WHICH IN TURN DEVELOPS A RETURN
SOUTHERLY FLOW OVER THE FORECAST AREA. THIS RETURN FLOW HELPS TO
DEFLECT THE BRIEF COOLING THE HIGH BRINGS IN THIS MORNING...CAUSING
HIGH TEMPERATURES TODAY TO END UP SIMILAR TO YESTERDAY. NOTE ANY FOG
SHOULD MIX OUT QUICKLY BETWEEN 9-10 AM.
HEADING INTO TONIGHT...AS THE SHORTWAVE COMES INTO THE DAKOTAS...
DPVA ASSOCIATED WITH IT LOOKS TO INTERACT WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. 850MB MOISTURE TRANSPORT PROGS FROM
THE 23.00Z NAM/GFS/REGIONAL CANADIAN AND ECMWF ALL POINT TO
CONVECTION BREAKING OUT ACROSS EASTERN SOUTH DAKOTA THIS EVENING...
ON THE NOSE OF ENHANCED MOISTURE TRANSPORT WITHIN THE LOW LEVEL JET.
THIS CONVECTION THEN TRANSLATES EAST. MODEL CONSENSUS WOULD SUGGEST
THE BULK OF THE CONVECTION STAYS WEST OF THE AREA PRIOR TO 12Z
SATURDAY...BUT DID INCLUDE A 20-30 PERCENT CHANCE OVER WESTERN
PORTIONS OF THE FORECAST AREA IN THE EVENT SOME STORMS FORM ON THE
EASTERN EDGE OF THE MOISTURE TRANSPORT AS INDICATED BY THE 23.00Z
NAM. COMBINATION OF INCREASING MID CLOUDS WITH THE MOISTURE
TRANSPORT...AS WELL AS SURFACE WINDS...WILL RESULT IN A WARMER
NIGHT. A BLEND OF MODEL GUIDANCE LOOKS REASONABLE FOR LOWS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 258 AM CDT FRI AUG 23 2013
HAZARDS...
THE BIG ONE HERE IS HEAT. A LONG DURATION HEAT EVENT APPEARS
LIKELY...BEGINNING ON SUNDAY AND MOSTLY LASTING THROUGH THE REST OF
THE LONG TERM PERIOD AND BEYOND. HOWEVER...WEDNESDAY AND THURSDAY
ARE MOST PROBLEMATIC AND HAVE PRECLUDED ISSUING ANY HEAT HAZARDS AT
THIS TIME. SOME HEAT HAZARDS WILL BE NEEDED EVENTUALLY... ESPECIALLY
FOR MONDAY AND TUESDAY.
SYNOPTIC OVERVIEW...
23.00Z ECMWF/GFS/CANADIAN AND THE PORTION OF THE NAM THROUGH 84
HOURS ARE ALL IN GOOD AGREEMENT THAT THE UPPER PATTERN CHANGES VERY
LITTLE FROM WHERE IT ENDS UP AT 12Z SATURDAY THROUGH THE ENTIRE LONG
TERM PERIOD. THE UPPER RIDGE AXIS APPEARS TO STAY CENTERED OVER
MINNESOTA WHILE THE SUBTROPICAL HIGH CENTER STRENGTHENS OVER KANSAS
AND MISSOURI DURING THE WEEKEND. VARIOUS SHORTWAVES OF MONSOONAL
ORIGIN AND ENHANCED BY CONVECTION WILL ROTATE AROUND THE RIDGE...
MOST OF WHICH APPEAR TO TAKE A TRACK THROUGH THE DAKOTAS...NORTHERN
MINNESOTA AND THROUGH MICHIGAN AND NORTHERN WISCONSIN. THIS IS A
PATTERN MORE TYPICAL OF JULY OR EARLY AUGUST VERSUS LATE AUGUST. THE
BIG FORECAST QUESTION FROM THE PRECIPITATION SIDE OF THINGS WILL BE
DOES ANY CONVECTION ASSOCIATED WITH THE SHORTWAVES DROP SOUTH INTO
THE FORECAST AREA. OTHERWISE...ITS ALL ABOUT HOW HOT IT WILL BE.
PRECIPITATION DETAILS...
FOR SATURDAY...ALTHOUGH ALL INDICATIONS ARE THAT THE NOSE OF THE
850MB MOISTURE TRANSPORT WILL SHIFT NORTH UP INTO NORTHWEST
ONTARIO...THE FORECAST AREA SITS ON THE EASTERN EDGE OF THE
MOISTURE TRANSPORT. THE NAM...GFS...ECMWF AND REGIONAL CANADIAN
ALL DEVELOP SCATTERED CONVECTION THROUGHOUT THE DAY...DUE TO THE
COMBINATION OF THIS MOISTURE TRANSPORT AND ELEVATED INSTABILITY
ROOTED AT OR ABOVE 900MB. ADDITIONALLY...WE HAVE THAT SHORTWAVE
COMING FROM THE DAKOTAS TO PROVIDE SOME DPVA HELP. THEREFORE...
HAVE 20-40 PERCENT CHANCES IN THE FORECAST. 1-6KM SHEAR VALUES OF
20-25 KT SHOULD PRECLUDE ANY ORGANIZED SEVERE THREAT...THOUGH
INCREASING PRECIPITABLE WATER VALUES SUGGEST POTENTIAL FOR SOME
LOCALLY HEAVY RAIN.
PRECIPITATION CHANCES SHOULD BEGIN TO SHIFT NORTH SATURDAY NIGHT
WITH THE SHORTWAVE PASSED...THE NOSE OF THE 850MB MOISTURE TRANSPORT
CENTERED FROM NORTHWEST ONTARIO INTO UPPER MI AND THE FORECAST AREA
BECOMING MORE UNDER THE MOISTURE TRANSPORT STREAM ITSELF. THE 23.00Z
GFS IS AN OUTLIER HAVING CONVECTION ALL THE WAY SOUTH TOWARDS
DUBUQUE WHEREAS ALL OTHER GUIDANCE SUGGESTS ALONG/NORTH I-94 OR EVEN
NORTH OF THE FORECAST AREA. LEANED AWAY FROM THE GFS...WHICH STAYS
IN GOOD CONTINUITY WITH THE PREVIOUS FORECAST. HIGH CONFIDENCE THAT
CONVECTION WILL STAY WELL OFF TO THE NORTHEAST SUNDAY. ANOTHER
MONSOON-RELATED SHORTWAVE IS SUGGESTED BY SOME MODELS TO COME ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT. THE AIRMASS MAY
BE CAPPED OFF EVEN TO ELEVATED CONVECTION...BUT WITH THE 22.12Z
ECMWF AND 23.00Z GFS DEPICTING SOME CONVECTION WITH THE SHORTWAVE...
FELT A 20-30 PERCENT CHANCE IS NEEDED. 23.00Z ECMWF IS DRY FOR
SUNDAY NIGHT...WHICH MAY TURN OUT IN REALITY. FOR MONDAY AND
BEYOND...MODELS OCCASIONALLY PRODUCE CONVECTION...PARTICULARLY
ALONG AND NORTH AND EAST OF I-94 AS SHORTWAVES ROUND THE RIDGE.
FROM A CONSENSUS STANDPOINT...THIS YIELDS 20-30 PERCENT CHANCES
NEEDED EACH DAY IN THIS AREA.
TEMPERATURE DETAILS...
FOR SATURDAY...BETWEEN THE CONVECTION AROUND AS WELL AS INDICATIONS
OF PLENTY OF CIRRUS...TEMPERATURES ARE LIKELY NOT TO REACH THEIR
MAXIMUM POTENTIAL. 850MB TEMPS CLIMBING TO 16C EAST TO 19C WEST
WOULD SUPPORT HIGHS IN THE MID TO PERHAPS UPPER 80S...BUT THE
AFOREMENTIONED ISSUES LIKELY TO HOLD HIGH TEMPS 5-10 DEGREES COOLER.
TEMPERATURES REALLY BEGIN TO HEAT UP ON SUNDAY. COMBINATION OF 925MB
TEMPS CLIMBING TO 26-28C AND A BREEZY SOUTHWEST WIND SHOULD EASILY
PROPEL HIGHS INTO THE UPPER 80S TO LOW 90S. THE WINDS ARE ALSO GOING
TO ADVECT IN HIGHER DEWPOINTS...LIKELY IN THE UPPER 60S TO LOW 70S.
HEAT INDICES AS A RESULT TOP OUT IN THE 95 TO 100 RANGE.
MONDAY AND TUESDAY BOTH LOOK HOT AS THE WARM AIR SHIFTS EAST OVER
THE FORECAST AREA. 925MB TEMPS RISE FURTHER TO 27-29C...PERHAPS EVEN
30C. WITH PLENTY OF SUN...ESPECIALLY SOUTHWEST OF I-94...HIGHS OF
90-95 SHOULD OCCUR. DEWPOINTS MAY NOT CHANGE MUCH COMPARED TO
SUNDAY...CAUSING HEAT INDICES TO LIKELY JUMP TO 100-105. THESE
DAYS WILL NEED AT LEAST A HEAT ADVISORY.
WEDNESDAY AND THURSDAY BECAME A BIT MORE UNCERTAIN WITH THE 23.00Z
ECMWF/UKMET. THEY HAVE A SHORTWAVE TROUGH DIGGING INTO NEW ENGLAND
WHICH ALLOWS A BACK DOOR COLD FRONT TO COME THROUGH THE FORECAST
AREA. 925MB TEMPS COOL TO 24-26C...WHICH WOULD KEEP HIGHS PERHAPS
EVEN BELOW 90. ON THE OTHER HAND...THE 23.00Z GFS DOESNT DROP THE
COLD FRONT THROUGH...KEEPING 925MB TEMPS UP BETWEEN 28-32C. FOR
NOW FOLLOWED A CONSENSUS...WHICH RESULTS IN THESE DAYS BELOW HEAT
ADVISORY CONDITIONS.
LOWS WILL STAY QUITE WARM DURING THIS STRETCH...LIKELY IN THE LOW
TO MID 70S EVERY NIGHT.
GIVEN THE UNCERTAINTY WITH WEDNESDAY AND THURSDAY...AND THE VERY
MARGINAL CONDITIONS ON SUNDAY...HAVE NOT ISSUED ANY HEAT HAZARDS
AT THIS TIME.
NOTE THAT MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1155 PM CDT THU AUG 22 2013
CHALLENGING RIVER VALLEY FOG SETUP FOR KLSE AS A FEW COMPETING
FACTORS COULD LEAD TO 1/4SM...OR NOTHING AT ALL. AS HIGH PRESSURE
SETTLES TO THE NORTH...SOUTHEASTERLY SURFACE WINDS WILL REMAIN
GENERALLY 5 MPH OR LESS. HOWEVER...925 TO 900 MB WINDS ARE EXPECTED
TO INCREASE FROM 5 TO 7 MPH THIS EVENING...TO NEARLY 15 TO 20 MPH BY
10Z ACCORDING TO VARIOUS MODEL SOUNDINGS. THIS WIND INCREASE DOES
NOT SUPPORT A DENSE FOG EVENT. HOWEVER...THE LATE ARRIVAL OF THIS
SPEED MAX COULD ALLOW FOG TO FORM IN THE CHANNEL...THEN TRAP IT
BELOW THE INVERSION. ALSO...TRENDS IN THE MODEL SOUNDINGS ARE NOT AS
CONSISTENT...AND SOME PREVIOUS RUNS SHOWED A LIGHTER WIND LAYER. ALL
IN ALL...WHILE THE WIND ISSUE MAY HURT DENSE FOG CHANCES...NOT SOLD
YET THAT IT WILL PRECLUDE DENSE FOG FORMATION. T/TD IS DOWN TO 5 F
AS OF 04Z...WITH SFC WINDS REMAINING LIGHT. BOTH FAVORABLE FOR DENSE
FOG. KLSE TAF WAS UPDATED BEFORE 03Z TO INCLUDE A PERIOD OF
1/4SM...AND WILL CONTINUE THIS. EXPECT RAPID IMPROVEMENT/CLEARING
AROUND 14Z. REST OF THE DAY SHOULD BE VFR...WITH CLOUDS INCREASING
OVERNIGHT FRIDAY...AND THE CHANCE FOR SCT SHRA/TS ON SAT.
&&
.CLIMATE...
ISSUED AT 343 AM CDT FRI AUG 23 2013
GIVEN THE UPCOMING STRETCH OF HEAT...HERE ARE SOME RECORD HIGHS FOR
LA CROSSE AND ROCHESTER THROUGH LABOR DAY WEEKEND. MORE CLIMATE
INFORMATION CAN BE FOUND ON OUR WEBSITE IN THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGHS ARE 78-80 AT LA CROSSE AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ054-055-
061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....ZT/RIECK
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
258 AM CDT FRI AUG 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 258 AM CDT FRI AUG 23 2013
MAIN FORECAST CONCERN IN THE SHORT TERM IS ON PRECIPITATION CHANCES
TONIGHT.
CURRENTLY AS OF 07Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
JUST OFF THE WEST COAST OF THE U.S....RIDGING COVERING MUCH OF THE
PLAINS...AND TROUGHING IN SOUTHEAST CANADA. VARIOUS MONSOONAL
RELATED SHORTWAVES WERE ROTATING AROUND THE UPPER RIDGE ACROSS THE
U.S. ROCKIES...WITH THE MAIN SYNOPTIC SHORTWAVE OF NOTE OVER
OREGON. THE FORECAST AREA LIES IN THE INFLECTION OF THE RIDGE AND
TROUGH...RESULTING IN SUBSIDENCE AND DRYING. THIS IS REFLECTED
WELL BY HIGH PRESSURE THAT IS CENTERED OVER UPPER MICHIGAN...ALONG
WITH 00Z RAOBS FROM MPX AND GRB WHICH HAD PRECIPITABLE WATER
VALUES OF 0.94 AND 0.81 RESPECTIVELY. THESE VALUES ARE MUCH LOWER
THAN THE 1.8-2 INCH VALUES THAT WERE PRESENT ALONG/SOUTH OF I-90
AT 12Z YESTERDAY WITH THE MCS THAT ROLLED THROUGH. LIGHT WINDS
ASSOCIATED WITH THE HIGH...GOOD RADIATIONAL COOLING
CONDITIONS...RECENT RAIN AND SURFACE DEWPOINTS WHICH CLIMBED FROM
EVENING EVAPOTRANSPORATION HAS LED TO SOME FOG. THE THICKEST FOG
IS OVER NORTHEAST IA AND FAR SOUTHWEST WI WHERE A DENSE FOG
ADVISORY WAS JUST ISSUED. AIRMASS OVER THE FORECAST AREA REMAINS
RELATIVELY WARM WITH 850MB READINGS OF 14-16C...WHICH ARE NORMAL.
HOWEVER...TO THE WEST...MUCH WARMER 850MB TEMPS OF 20-25C HAVE
SPREAD NORTH FROM THE CENTRAL PLAINS INTO MONTANA.
SYNOPTIC OVERVIEW...
MODELS ARE IN GOOD AGREEMENT PUSHING THE UPPER RIDGE GRADUALLY
EASTWARD DURING THE NEXT 24 HOURS...SUCH THAT AT 12Z SATURDAY THE
RIDGE AXIS EXTENDS INTO MINNESOTA WITH THE SUBTROPICAL HIGH CENTERED
OVER KANSAS AND MISSOURI. THE BIGGEST CONCERN IS ON THE MONSOONAL
SHORTWAVES ROTATING AROUND THE RIDGE. ONE SUCH SHORTWAVE MODELS
SUGGEST COMING ACROSS THE DAKOTAS INTO WESTERN MINNESOTA
TONIGHT...WHICH COULD TRY TO SPREAD SOME PRECIP EAST TOWARDS THE
FORECAST AREA.
DETAILS...
QUIET CONDITIONS TODAY WITH THE FORECAST AREA UNDER THE INFLUENCE OF
THE HIGH PRESSURE AREA OVER UPPER MICHIGAN. NOTE THAT THE HIGH DOES
START DRIFTING OFF TO THE EAST...WHICH IN TURN DEVELOPS A RETURN
SOUTHERLY FLOW OVER THE FORECAST AREA. THIS RETURN FLOW HELPS TO
DEFLECT THE BRIEF COOLING THE HIGH BRINGS IN THIS MORNING...CAUSING
HIGH TEMPERATURES TODAY TO END UP SIMILAR TO YESTERDAY. NOTE ANY FOG
SHOULD MIX OUT QUICKLY BETWEEN 9-10 AM.
HEADING INTO TONIGHT...AS THE SHORTWAVE COMES INTO THE DAKOTAS...
DPVA ASSOCIATED WITH IT LOOKS TO INTERACT WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. 850MB MOISTURE TRANSPORT PROGS FROM
THE 23.00Z NAM/GFS/REGIONAL CANADIAN AND ECMWF ALL POINT TO
CONVECTION BREAKING OUT ACROSS EASTERN SOUTH DAKOTA THIS EVENING...
ON THE NOSE OF ENHANCED MOISTURE TRANSPORT WITHIN THE LOW LEVEL JET.
THIS CONVECTION THEN TRANSLATES EAST. MODEL CONSENSUS WOULD SUGGEST
THE BULK OF THE CONVECTION STAYS WEST OF THE AREA PRIOR TO 12Z
SATURDAY...BUT DID INCLUDE A 20-30 PERCENT CHANCE OVER WESTERN
PORTIONS OF THE FORECAST AREA IN THE EVENT SOME STORMS FORM ON THE
EASTERN EDGE OF THE MOISTURE TRANSPORT AS INDICATED BY THE 23.00Z
NAM. COMBINATION OF INCREASING MID CLOUDS WITH THE MOISTURE
TRANSPORT...AS WELL AS SURFACE WINDS...WILL RESULT IN A WARMER
NIGHT. A BLEND OF MODEL GUIDANCE LOOKS REASONABLE FOR LOWS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 258 AM CDT FRI AUG 23 2013
HAZARDS...
THE BIG ONE HERE IS HEAT. A LONG DURATION HEAT EVENT APPEARS
LIKELY...BEGINNING ON SUNDAY AND MOSTLY LASTING THROUGH THE REST OF
THE LONG TERM PERIOD AND BEYOND. HOWEVER...WEDNESDAY AND THURSDAY
ARE MOST PROBLEMATIC AND HAVE PRECLUDED ISSUING ANY HEAT HAZARDS AT
THIS TIME. SOME HEAT HAZARDS WILL BE NEEDED EVENTUALLY... ESPECIALLY
FOR MONDAY AND TUESDAY.
SYNOPTIC OVERVIEW...
23.00Z ECMWF/GFS/CANADIAN AND THE PORTION OF THE NAM THROUGH 84
HOURS ARE ALL IN GOOD AGREEMENT THAT THE UPPER PATTERN CHANGES VERY
LITTLE FROM WHERE IT ENDS UP AT 12Z SATURDAY THROUGH THE ENTIRE LONG
TERM PERIOD. THE UPPER RIDGE AXIS APPEARS TO STAY CENTERED OVER
MINNESOTA WHILE THE SUBTROPICAL HIGH CENTER STRENGTHENS OVER KANSAS
AND MISSOURI DURING THE WEEKEND. VARIOUS SHORTWAVES OF MONSOONAL
ORIGIN AND ENHANCED BY CONVECTION WILL ROTATE AROUND THE RIDGE...
MOST OF WHICH APPEAR TO TAKE A TRACK THROUGH THE DAKOTAS...NORTHERN
MINNESOTA AND THROUGH MICHIGAN AND NORTHERN WISCONSIN. THIS IS A
PATTERN MORE TYPICAL OF JULY OR EARLY AUGUST VERSUS LATE AUGUST. THE
BIG FORECAST QUESTION FROM THE PRECIPITATION SIDE OF THINGS WILL BE
DOES ANY CONVECTION ASSOCIATED WITH THE SHORTWAVES DROP SOUTH INTO
THE FORECAST AREA. OTHERWISE...ITS ALL ABOUT HOW HOT IT WILL BE.
PRECIPITATION DETAILS...
FOR SATURDAY...ALTHOUGH ALL INDICATIONS ARE THAT THE NOSE OF THE
850MB MOISTURE TRANSPORT WILL SHIFT NORTH UP INTO NORTHWEST
ONTARIO...THE FORECAST AREA SITS ON THE EASTERN EDGE OF THE
MOISTURE TRANSPORT. THE NAM...GFS...ECMWF AND REGIONAL CANADIAN
ALL DEVELOP SCATTERED CONVECTION THROUGHOUT THE DAY...DUE TO THE
COMBINATION OF THIS MOISTURE TRANSPORT AND ELEVATED INSTABILITY
ROOTED AT OR ABOVE 900MB. ADDITIONALLY...WE HAVE THAT SHORTWAVE
COMING FROM THE DAKOTAS TO PROVIDE SOME DPVA HELP. THEREFORE...
HAVE 20-40 PERCENT CHANCES IN THE FORECAST. 1-6KM SHEAR VALUES OF
20-25 KT SHOULD PRECLUDE ANY ORGANIZED SEVERE THREAT...THOUGH
INCREASING PRECIPITABLE WATER VALUES SUGGEST POTENTIAL FOR SOME
LOCALLY HEAVY RAIN.
PRECIPITATION CHANCES SHOULD BEGIN TO SHIFT NORTH SATURDAY NIGHT
WITH THE SHORTWAVE PASSED...THE NOSE OF THE 850MB MOISTURE TRANSPORT
CENTERED FROM NORTHWEST ONTARIO INTO UPPER MI AND THE FORECAST AREA
BECOMING MORE UNDER THE MOISTURE TRANSPORT STREAM ITSELF. THE 23.00Z
GFS IS AN OUTLIER HAVING CONVECTION ALL THE WAY SOUTH TOWARDS
DUBUQUE WHEREAS ALL OTHER GUIDANCE SUGGESTS ALONG/NORTH I-94 OR EVEN
NORTH OF THE FORECAST AREA. LEANED AWAY FROM THE GFS...WHICH STAYS
IN GOOD CONTINUITY WITH THE PREVIOUS FORECAST. HIGH CONFIDENCE THAT
CONVECTION WILL STAY WELL OFF TO THE NORTHEAST SUNDAY. ANOTHER
MONSOON-RELATED SHORTWAVE IS SUGGESTED BY SOME MODELS TO COME ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT. THE AIRMASS MAY
BE CAPPED OFF EVEN TO ELEVATED CONVECTION...BUT WITH THE 22.12Z
ECMWF AND 23.00Z GFS DEPICTING SOME CONVECTION WITH THE SHORTWAVE...
FELT A 20-30 PERCENT CHANCE IS NEEDED. 23.00Z ECMWF IS DRY FOR
SUNDAY NIGHT...WHICH MAY TURN OUT IN REALITY. FOR MONDAY AND
BEYOND...MODELS OCCASIONALLY PRODUCE CONVECTION...PARTICULARLY
ALONG AND NORTH AND EAST OF I-94 AS SHORTWAVES ROUND THE RIDGE.
FROM A CONSENSUS STANDPOINT...THIS YIELDS 20-30 PERCENT CHANCES
NEEDED EACH DAY IN THIS AREA.
TEMPERATURE DETAILS...
FOR SATURDAY...BETWEEN THE CONVECTION AROUND AS WELL AS INDICATIONS
OF PLENTY OF CIRRUS...TEMPERATURES ARE LIKELY NOT TO REACH THEIR
MAXIMUM POTENTIAL. 850MB TEMPS CLIMBING TO 16C EAST TO 19C WEST
WOULD SUPPORT HIGHS IN THE MID TO PERHAPS UPPER 80S...BUT THE
AFOREMENTIONED ISSUES LIKELY TO HOLD HIGH TEMPS 5-10 DEGREES COOLER.
TEMPERATURES REALLY BEGIN TO HEAT UP ON SUNDAY. COMBINATION OF 925MB
TEMPS CLIMBING TO 26-28C AND A BREEZY SOUTHWEST WIND SHOULD EASILY
PROPEL HIGHS INTO THE UPPER 80S TO LOW 90S. THE WINDS ARE ALSO GOING
TO ADVECT IN HIGHER DEWPOINTS...LIKELY IN THE UPPER 60S TO LOW 70S.
HEAT INDICES AS A RESULT TOP OUT IN THE 95 TO 100 RANGE.
MONDAY AND TUESDAY BOTH LOOK HOT AS THE WARM AIR SHIFTS EAST OVER
THE FORECAST AREA. 925MB TEMPS RISE FURTHER TO 27-29C...PERHAPS EVEN
30C. WITH PLENTY OF SUN...ESPECIALLY SOUTHWEST OF I-94...HIGHS OF
90-95 SHOULD OCCUR. DEWPOINTS MAY NOT CHANGE MUCH COMPARED TO
SUNDAY...CAUSING HEAT INDICES TO LIKELY JUMP TO 100-105. THESE
DAYS WILL NEED AT LEAST A HEAT ADVISORY.
WEDNESDAY AND THURSDAY BECAME A BIT MORE UNCERTAIN WITH THE 23.00Z
ECMWF/UKMET. THEY HAVE A SHORTWAVE TROUGH DIGGING INTO NEW ENGLAND
WHICH ALLOWS A BACK DOOR COLD FRONT TO COME THROUGH THE FORECAST
AREA. 925MB TEMPS COOL TO 24-26C...WHICH WOULD KEEP HIGHS PERHAPS
EVEN BELOW 90. ON THE OTHER HAND...THE 23.00Z GFS DOESNT DROP THE
COLD FRONT THROUGH...KEEPING 925MB TEMPS UP BETWEEN 28-32C. FOR
NOW FOLLOWED A CONSENSUS...WHICH RESULTS IN THESE DAYS BELOW HEAT
ADVISORY CONDITIONS.
LOWS WILL STAY QUITE WARM DURING THIS STRETCH...LIKELY IN THE LOW
TO MID 70S EVERY NIGHT.
GIVEN THE UNCERTAINTY WITH WEDNESDAY AND THURSDAY...AND THE VERY
MARGINAL CONDITIONS ON SUNDAY...HAVE NOT ISSUED ANY HEAT HAZARDS
AT THIS TIME.
NOTE THAT MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1155 PM CDT THU AUG 22 2013
CHALLENGING RIVER VALLEY FOG SETUP FOR KLSE AS A FEW COMPETING
FACTORS COULD LEAD TO 1/4SM...OR NOTHING AT ALL. AS HIGH PRESSURE
SETTLES TO THE NORTH...SOUTHEASTERLY SURFACE WINDS WILL REMAIN
GENERALLY 5 MPH OR LESS. HOWEVER...925 TO 900 MB WINDS ARE EXPECTED
TO INCREASE FROM 5 TO 7 MPH THIS EVENING...TO NEARLY 15 TO 20 MPH BY
10Z ACCORDING TO VARIOUS MODEL SOUNDINGS. THIS WIND INCREASE DOES
NOT SUPPORT A DENSE FOG EVENT. HOWEVER...THE LATE ARRIVAL OF THIS
SPEED MAX COULD ALLOW FOG TO FORM IN THE CHANNEL...THEN TRAP IT
BELOW THE INVERSION. ALSO...TRENDS IN THE MODEL SOUNDINGS ARE NOT AS
CONSISTENT...AND SOME PREVIOUS RUNS SHOWED A LIGHTER WIND LAYER. ALL
IN ALL...WHILE THE WIND ISSUE MAY HURT DENSE FOG CHANCES...NOT SOLD
YET THAT IT WILL PRECLUDE DENSE FOG FORMATION. T/TD IS DOWN TO 5 F
AS OF 04Z...WITH SFC WINDS REMAINING LIGHT. BOTH FAVORABLE FOR DENSE
FOG. KLSE TAF WAS UPDATED BEFORE 03Z TO INCLUDE A PERIOD OF
1/4SM...AND WILL CONTINUE THIS. EXPECT RAPID IMPROVEMENT/CLEARING
AROUND 14Z. REST OF THE DAY SHOULD BE VFR...WITH CLOUDS INCREASING
OVERNIGHT FRIDAY...AND THE CHANCE FOR SCT SHRA/TS ON SAT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ054-055-
061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....ZT/RIECK
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1045 PM PDT SAT AUG 24 2013
NEW AVIATION DISCUSSION
.SYNOPSIS...
DRY WEATHER WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES CAN
BE EXPECTED THROUGH SUNDAY. A MOIST AIR MASS FROM THE SOUTH WILL
BRING THE SLIGHT CHANCE OF THUNDERSTORMS TO THE LOS ANGELES COUNTY
MOUNTAINS AND ANTELOPE VALLEY MONDAY...THEN TO MUCH OF VENTURA AND
LOS ANGELES COUNTIES MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL
RIDGE OF HIGH PRESSURE WILL BUILD INTO SOUTHERN CALIFORNIA BY THE
MIDDLE TO END OF NEXT WEEK WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.UPDATE...
ONSHORE FLOW REMAINS IN PLACE ACROSS THE AREA THIS EVENING ALONG
WITH A STUBBORN MARINE LAYER. THE LATEST MODEL SOLUTIONS CONTINUE
TO SUGGEST ONSHORE FLOW WEAKENING ACROSS THE AREA ON SUNDAY ALONG
WITH INCREASING 500 MB HEIGHTS. WITH THIS MIND...A WARMING TREND
REMAINS INTACT ACROSS THE AREA...ESPECIALLY ALONG THE COAST.
THE FORECAST WILL HAVE TO BE MONITORED FOR DEVELOPMENT AS
MOISTURE IS STARTING TO PUSH INTO THE HIGH DESERTS OF SOUTHERN
CALIFORNIA. CURRENTLY...THE PACKAGE HAS NO POPS OR WEATHER FOR THE
ANTELOPE VALLEY. HOWEVER...KVCV DEW POINTS HAVE SURGED INTO THE
LOWER 50S THIS HOUR...AND KL35 INTO THE 40S. MODEL SOLUTIONS
CONTINUE TO KEEP THE BEST MOISTURE AND INSTABILITY SOUTH AND EAST
OF THE AREA...BUT DEW POINT DEVELOPMENTS ARE STARTING TO BE
PROBLEMATIC. 13-KM RAP MODEL SOLUTION ARE ALSO STARTING HINT AT
THE POSSIBILITY OF CONVECTIVE STORM OVER THE EASTERN SAN GABRIEL
RANGE. THE NEXT SHIFT WILL BE BRIEFED ACCORDINGLY.
&&
.PREV DISCUSSION...
SHORT TERM...12Z MODELS TODAY STARTED TO SHOW A RETURN OF IVO
MOISTURE BACK INTO THE EASTERN PART OF OUR FORECAST AREA MONDAY
AND ESPECIALLY MONDAY NIGHT INTO TUESDAY. THE GFS AND GEM MODELS
HAD SHOWN THIS AT ONE TIME BUT BACKED OFF IN FAVOR OF THE TROF TO
THE NORTH USHERING IN MORE DRY AIR FROM THE SOUTHWEST AND PUSHING
THE MOISTURE EAST. THE NAM IS THE MOST AGGRESSIVE WITH THE
MOISTURE BUT ALL MODELS SHOW A PRETTY DRAMATIC INCREASE FROM THE
SOLUTIONS OVER THE LAST COUPLE DAYS. THIS COULD BE JUST A BRIEF
FLING WITH WETTER SOLUTIONS BEFORE WAGGING BACK TO A DRIER
SOLUTION TONIGHT OR SUNDAY BUT GIVEN THE CONSENSUS IT SEEMS
WARRANTED TO RE-INTRODUCE AT LEAST SOME LOW CHANCES OF
SHOWERS/STORMS TO LA/VENTURA COUNTIES MONDAY NIGHT INTO TUESDAY.
THE NAM ALSO SHOWS RESPECTABLE CAPE AS WELL AS K/LIFTED INDICES
DURING THAT TIME, THOUGH MODEL SOUNDINGS ACROSS SOUTHERN LA COUNTY
SEEMED TO SUGGEST MORE OF A STRATIFORM PRECIP EVENT
(SPRINKLES/LIGHT SHOWERS) RATHER THAN A CONVECTIVE ONE WITH
COOLING IN THE LOWER LVLS AND SOME WARMING ALOFT. PWATS INCREASE
TO AN IMPRESSIVE 1.75-2" MONDAY NIGHT AND EARLY TUESDAY FOR
LA/VENTURA COUNTIES WHILE 850 DEW POINTS INCREASE TO BETWEEN
12-14C. BY TUESDAY AFTERNOON PRECIP THREAT SHOULD BE CONFINED TO
THE MOUNTAINS WHERE THE MOST UNSTABLE AIR WILL BE.
LONG TERM...A BREAK EXPECTED IN THE MONSOON SURGE ON WEDNESDAY
BEFORE MORE MOISTURE ARRIVES STARTING THURSDAY AND CONTINUING INTO
THE WEEKEND. ADDED SOME TSTM CHANCES BACK TO THE MOUNTAINS AND
ANTELOPE VALLEY BUT LEAVING COASTAL/VALLEY AREAS DRY FOR NOW. AT
THE SAME TIME HIGH PRESSURE OVER THE SOUTHWEST IS EXPECTED TO
EXPAND OVER CALIFORNIA AND BRING A WARMING TREND TO THE AREA.
LOOKING BEYOND THAT THE NEXT TROPICAL CYCLONE IS EXPECTED TO
DEVELOP OFF SOUTHERN MEXICO AROUND THE MIDDLE OF NEXT WEEK AND
EVENTUALLY BRING YET ANOTHER SURGE OF MOISTURE TO THE AREA LATE
NEXT WEEKEND OR EARLY THE FOLLOWING WEEK. SO WE`RE LOOKING AT AN
EXTENDED PERIOD OF POTENTIALLY WARM AND MUGGY CONDITIONS, WHICH IS
TO BE EXPECTED THIS TIME OF YEAR.
&&
.AVIATION...
25/0545Z
SHALLOW 900 FOOT DEEP MARINE LAYER COMBINED WITH A WEAK EDDY WILL
BRING LIFR TO IFR CIGS TO THE COASTAL TAF SITES OVERNIGHT. ARRIVAL
TIMING COULD BE AS MUCH AS TWO HOURS OFF BUT BETTER CONFIDENCE IN
CLEARING TIMES.
KLAX...GOOD CONFIDENCE IN TAF CIGS COULD BOUNCE FROM LIFR TO IFR
BETWEEN 07Z-13Z. NOTE: PREVAILING 1/4SM VIS IS A RESULT OF THE
OBSERVATION DECKS ELEVATED TOWER LOCATION. TAF VIS REFLECTS THE
ACTUAL SFC VIS.
KBUR...HIGH CONFIDENCE IN CAVU TAF.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL/MW
AVIATION...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
918 PM PDT SAT AUG 24 2013
.SYNOPSIS...
DRY WEATHER WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES CAN
BE EXPECTED THROUGH SUNDAY. A MOIST AIR MASS FROM THE SOUTH WILL
BRING THE SLIGHT CHANCE OF THUNDERSTORMS TO THE LOS ANGELES COUNTY
MOUNTAINS AND ANTELOPE VALLEY MONDAY...THEN TO MUCH OF VENTURA AND
LOS ANGELES COUNTIES MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL
RIDGE OF HIGH PRESSURE WILL BUILD INTO SOUTHERN CALIFORNIA BY THE
MIDDLE TO END OF NEXT WEEK WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.UPDATE...
ONSHORE FLOW REMAINS IN PLACE ACROSS THE AREA THIS EVENING ALONG
WITH A STUBBORN MARINE LAYER. THE LATEST MODEL SOLUTIONS CONTINUE
TO SUGGEST ONSHORE FLOW WEAKENING ACROSS THE AREA ON SUNDAY ALONG
WITH INCREASING 500 MB HEIGHTS. WITH THIS MIND...A WARMING TREND
REMAINS INTACT ACROSS THE AREA...ESPECIALLY ALONG THE COAST.
THE FORECAST WILL HAVE TO BE MONITORED FOR DEVELOPMENT AS
MOISTURE IS STARTING TO PUSH INTO THE HIGH DESERTS OF SOUTHERN
CALIFORNIA. CURRENTLY...THE PACKAGE HAS NO POPS OR WEATHER FOR THE
ANTELOPE VALLEY. HOWEVER...KVCV DEW POINTS HAVE SURGED INTO THE
LOWER 50S THIS HOUR...AND KL35 INTO THE 40S. MODEL SOLUTIONS
CONTINUE TO KEEP THE BEST MOISTURE AND INSTABILITY SOUTH AND EAST
OF THE AREA...BUT DEW POINT DEVELOPMENTS ARE STARTING TO BE
PROBLEMATIC. 13-KM RAP MODEL SOLUTION ARE ALSO STARTING HINT AT
THE POSSIBILITY OF CONVECTIVE STORM OVER THE EASTERN SAN GABRIEL
RANGE. THE NEXT SHIFT WILL BE BRIEFED ACCORDINGLY.
&&
.PREV DISCUSSION...
SHORT TERM...12Z MODELS TODAY STARTED TO SHOW A RETURN OF IVO
MOISTURE BACK INTO THE EASTERN PART OF OUR FORECAST AREA MONDAY
AND ESPECIALLY MONDAY NIGHT INTO TUESDAY. THE GFS AND GEM MODELS
HAD SHOWN THIS AT ONE TIME BUT BACKED OFF IN FAVOR OF THE TROF TO
THE NORTH USHERING IN MORE DRY AIR FROM THE SOUTHWEST AND PUSHING
THE MOISTURE EAST. THE NAM IS THE MOST AGGRESSIVE WITH THE
MOISTURE BUT ALL MODELS SHOW A PRETTY DRAMATIC INCREASE FROM THE
SOLUTIONS OVER THE LAST COUPLE DAYS. THIS COULD BE JUST A BRIEF
FLING WITH WETTER SOLUTIONS BEFORE WAGGING BACK TO A DRIER
SOLUTION TONIGHT OR SUNDAY BUT GIVEN THE CONSENSUS IT SEEMS
WARRANTED TO RE-INTRODUCE AT LEAST SOME LOW CHANCES OF
SHOWERS/STORMS TO LA/VENTURA COUNTIES MONDAY NIGHT INTO TUESDAY.
THE NAM ALSO SHOWS RESPECTABLE CAPE AS WELL AS K/LIFTED INDICES
DURING THAT TIME, THOUGH MODEL SOUNDINGS ACROSS SOUTHERN LA COUNTY
SEEMED TO SUGGEST MORE OF A STRATIFORM PRECIP EVENT
(SPRINKLES/LIGHT SHOWERS) RATHER THAN A CONVECTIVE ONE WITH
COOLING IN THE LOWER LVLS AND SOME WARMING ALOFT. PWATS INCREASE
TO AN IMPRESSIVE 1.75-2" MONDAY NIGHT AND EARLY TUESDAY FOR
LA/VENTURA COUNTIES WHILE 850 DEW POINTS INCREASE TO BETWEEN
12-14C. BY TUESDAY AFTERNOON PRECIP THREAT SHOULD BE CONFINED TO
THE MOUNTAINS WHERE THE MOST UNSTABLE AIR WILL BE.
LONG TERM...A BREAK EXPECTED IN THE MONSOON SURGE ON WEDNESDAY
BEFORE MORE MOISTURE ARRIVES STARTING THURSDAY AND CONTINUING INTO
THE WEEKEND. ADDED SOME TSTORM CHANCES BACK TO THE MOUNTAINS AND
ANTELOPE VALLEY BUT LEAVING COASTAL/VALLEY AREAS DRY FOR NOW. AT
THE SAME TIME HIGH PRESSURE OVER THE SOUTHWEST IS EXPECTED TO
EXPAND OVER CALIFORNIA AND BRING A WARMING TREND TO THE AREA.
LOOKING BEYOND THAT THE NEXT TROPICAL CYCLONE IS EXPECTED TO
DEVELOP OFF SOUTHERN MEXICO AROUND THE MIDDLE OF NEXT WEEK AND
EVENTUALLY BRING YET ANOTHER SURGE OF MOISTURE TO THE AREA LATE
NEXT WEEKEND OR EARLY THE FOLLOWING WEEK. SO WE`RE LOOKING AT AN
EXTENDED PERIOD OF POTENTIALLY WARM AND MUGGY CONDITIONS, WHICH IS
TO BE EXPECTED THIS TIME OF YEAR.
&&
.AVIATION...25/0000Z.
AT COASTAL TERMINALS...LIFR TO IFR CONDITIONS WILL REDEVELOP THROUGH
11Z...POSSIBLY LOWERING ONE CATEGORY BETWEEN 08Z AND 15Z ESPECIALLY
NORTH OF POINT CONCEPTION. VFR CONDITIONS SHOULD REDEVELOP BETWEEN
16Z AND 18Z. THERE IS A SLIGHT CHANCE THAT SUB-VFR CONDITIONS COULD
LINGER BEYOND 18Z.
KLAX...IFR CONDITIONS WILL LIKELY PERSIST THROUGH AT LEAST
04Z...THEN LOWER TO LIFR BETWEEN 04Z AND 08Z. THERE IS A 30 PERCENT
CHANCE OF VLIFR CONDITIONS BETWEEN 08Z AND 15Z. VFR CONDITIONS
SHOULD REDEVELOP BETWEEN 16Z AND 18Z. THERE IS A 20 PERCENT CHANCE
THAT SUB-VFR CONDITIONS LINGERING BEYOND 18Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL/MW
AVIATION...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS GOODLAND KS
254 AM MDT SUN AUG 25 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1154 PM MDT SAT AUG 24 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT MCK AND GLD.
SOUTH WINDS WILL INCREASE AND BECOME GUSTY DURING THE DAY ON
SUNDAY BETWEEN 14Z AND 23Z AND WILL LOSE THE GUSTS FOLLOWING SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JJM
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS DULUTH MN
349 AM CDT SUN AUG 25 2013
.SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.AVIATION...06Z TAF ISSUANCE.
VFR CONDITIONS WILL PREVAIL MOST OF THE FCST PERIOD EXCEPT IN THE
NRN TIER OF MN WHERE LOCAL MVFR/IFR MAY OCCUR IN LOWER CLOUD
DEVELOPMENT AND HEAVIER STORMS EARLY THIS MORNING. A WEAK SFC BDRY
WILL TRY TO PUSH SOUTH ACROSS THE AREA TODAY. MID LVL WARMTH
SHOULD MAKE CONVECTION TOUGH TO DEVELOP. AMENDMENTS MAY BE
REQUIRED GIVEN UNCERTAINTY OF CONVECTIVE DEVELOPMENT. LLWS AT
KBRD/KHYR AS 45/50KT LLJ TRANSLATES EAST THROUGH 12Z.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....CANNON
AVIATION...CLC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
111 PM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 105 PM CDT FRI AUG 23 2013
EARLY THIS AFTERNOON...WARM FRONT ACROSS EASTERN MONTANA. EAST OF
THIS TROUGH A GOOD SOUTHEAST FLOW WAS BRING INCREASING DEW POINTS
INTO THE REGION. SOUNDING FORECAST SHOWS CENTRAL AND EAST WELL
CAPPED THIS AFTERNOON. THE WEST BECOMES UNCAPPED LATE IN THE DAY.
SO REMOVED MENTION OF THUNDERSTORMS THROUGH THE AFTERNOON. EXPECT
THE START OF CONVECTION THIS EVENING. OTHER ASPECTS OF THE
FORECAST LOOK GOOD.
UPDATE ISSUED AT 937 AM CDT FRI AUG 23 2013
WARM H500 RIDGE REMAINS OVER THE NORTHERN PLAINS TODAY. WITHIN THE
RIDGE THERE IS A WEAK VORT LOBE MOVING THROUGH WHICH...AIDED BY THE
DIURNAL LOW LEVEL JET...(30 KTS ON 12Z KBIS SOUNDING) SPONSORING
SOME WEAK CONVECTION CROSS THE SOUTH CENTRAL THIS MORNING.
CONVECTION EXPECTED TO DIMINISH AS THE LOW LEVEL FEATURES MIX OUT
THIS AM. THEN SYNOPTIC SCALE FORCING WILL PREVAIL THIS AFTERNOON
AND EVENING AS WARM FRONT IN EASTERN MONTANA MOVES EAST. THE WARM
FRONT WILL BE THE FOCUS FOR SCATTERED THUNDERSTORMS SOUTHWEST AND
WEST CENTRAL THIS AFTERNOON/EVENING. MADE SOME CHANGES TO CLOUDS
AND POPS THIS AM TO FOCUS ON THE ON GONG CONVECTION. OTHERWISE NO
OTHER CHANGES.
UPDATE ISSUED AT 643 AM CDT FRI AUG 23 2013
WEAK SHORTWAVE OVER SOUTHWEST NORTH DAKOTA IS PRODUCING ISOLATED
SHOWERS AND A FEW RUMBLES OF THUNDER OVER CENTRAL NORTH DAKOTA.
HAVE UPDATED POPS TO LATEST RADAR IMAGERY AND TRANSLATED THIS
NORTH AND EAST THROUGH MID MORNING. ALSO KEPT ISOLATED THUNDER
EXTENDING BACK INTO THE SOUTHWEST AS ANOTHER CELL HAD DEVELOPED
OVER THE FAR SOUTHWEST. OTHERWISE NO CHANGES TO THE CURRENT
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST CHALLENGE TODAY/TONIGHT WILL BE THUNDERSTORM
POTENTIAL AND AREAL COVERAGE.
LATEST WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL HIGH LOCATED OVER
SOUTHWEST KANSAS WITH RIDGING NORTH INTO EASTERN MONTANA. LOW
PRESSURE CIRCULATING OVER WESTERN OREGON IS EJECTING SEVERAL
SHORTWAVES INTO AND OVER THE RIDGE . THE 00Z MODEL GUIDANCE AND
HIGH RESOLUTION MODELS ALL OFFER DIFFERENT SCENARIOS FOR
CONVECTION TODAY INTO FRIDAY NIGHT. HIGHEST CONFIDENCE IS IN THE
NEAR TERM PERIOD WITH AN AREA OF SHOWERS AND THUNDERSTORMS IN
SOUTHEAST MONTANA MARCHING TOWARD SOUTHWEST NORTH DAKOTA. THE
LATEST HRRR HAS INITIALIZED WELL WITH THIS AREA AND WILL FOLLOW IT
FOR THE MORNING HOURS. ESSENTIALLY THIS AREA IS FORECAST TO SLIDE
ACROSS SOUTHWEST NORTH DAKOTA...THEN WEAKEN AND FALL APART AS IT
APPROACHES SOUTH CENTRAL NORTH DAKOTA LATER THIS MORNING. THE SHORTWAVE
CAUSING THIS PRECIPITATION IS SEEN OVER FAR SOUTHERN MONTANA NEAR
AND ALONG THE WYOMING BORDER. IT IS FORECAST TO CONTINUE TO PUSH
INTO SOUTHERN NORTH DAKOTA THIS AFTERNOON. VARIOUS CAPE/CIN
SOUNDINGS PROFILES PER NAM/GFS ARGUES FOR A MODEL BLEND AT THIS
TIME...AS IT IS UNCLEAR HOW MUCH OF A CAP REMAINS THIS AFTERNOON
INTO FRIDAY NIGHT. IT SEEMS REASONABLE THAT WITH A LEE SIDE
TROUGH IN EASTERN MONTANA TODAY...THIS WOULD BE THE AREA TO WATCH
FOR THE MOST INTENSE THUNDERSTORMS TO DEVELOP THIS AFTERNOON...WITH
CLOSE MONITORING THROUGH THE EVENING HOURS AS THEY MOVE NORTHEAST
INTO WESTERN NORTH DAKOTA. CURRENT THINKING IS ANY CONVECTION IN
CENTRAL NORTH DAKOTA THIS AFTERNOON SHOULD REMAIN ISOLATED IN
NATURE. H85 TEMPS WILL BE RISING AGAIN IN THE WEST WITH STRONG
WARM AIR ADVECTION RESULTING IN HIGHS IN THE LOW TO MID 90S.
FOR FRIDAY NIGHT...IT APPEARS THE MAIN FOCUS AND THREAT FOR SHOWERS
AND THUNDERSTORMS WILL RESIDE OVER NORTHERN NORTH DAKOTA. A SHORTWAVE
IS FORECAST TO MOVE ACROSS NORTHEAST MONTANA BY 06Z SATURDAY...AND
INTO SOUTHEASTERN SASKATCHEWAN BY 12Z SATURDAY. BEST FORCING IS IN
THE NORTH AND HAVE HIGH CHANCE POPS FORECAST OVERNIGHT WITH SLIGHT
CHANCE ELSEWHERE. OVERNIGHT LOWS WILL BE IN THE 60S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES...POSSIBLE HEAT ADVISORY HIGHLIGHTS AND PERIODIC
THUNDERSTORM CHANCES.
THERE IS A CONTINUED AGREEMENT IN THE MEAN UPPER LEVEL FLOW WHICH
FEATURES A STRONG RIDGE OVER THE CENTRAL U.S. THIS WILL RESULT IN
TEMPERATURES WELL ABOVE NORMAL THROUGH THE EXTENDED PERIOD ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. DAYTIME HIGHS FROM THE UPPER 80S
TO LOWER 90S NORTH AND LOWER TO MID 90S SOUTH ARE EXPECTED...WITH
SOME UPPER 90S AND LOWER 100 DEGREE READINGS QUITE POSSIBLE ACROSS
THE SOUTH. WITH DEWPOINTS GENERALLY IN THE 60S EACH DAY...AFTERNOON
HEAT INDICES WILL LIKELY APPROACH 100 DEGREES EACH DAY...ESPECIALLY
ACROSS THE SOUTH.
EVEN IN THE SHORT TERM MODELS ARE HAVING A HARD TIME RESOLVING
SHORTWAVES TRANSLATING THROUGH THE BROAD SOUTHWEST FLOW FROM THE
WESTERN UPPER LOW INTO THE NORTHERN PLAINS AND SOUTHERN CANADA.
THEREFORE A MODEL BLEND WAS UTILIZED FOR POPS THROUGH THE PERIOD.
MODELS ARE TRYING TO DEVELOP CONVECTION ON SATURDAY AND SATURDAY
NIGHT AS THERE WILL BE A SURFACE TROUGH TRACKING SLOWLY EAST ACROSS
THE AREA THAT IS PROGGED TO BE OVER CENTRAL NORTH DAKOTA BY 00 UTC
SUNDAY...WITH SHORTWAVE ENERGY MOVING INTO WESTERN NORTH DAKOTA. WE
WILL HAVE ABUNDANT CAPE OVER THE AREA SATURDAY AFTERNOON BUT WILL
LIKELY REMAIN CAPPED UNTIL SHORTWAVE ENERGY ARRIVES LATE IN THE DAY.
THUS THE BEST THUNDERSTORM CHANCES ON SATURDAY ARE EXPECTED TO BE IN
THE EVENING AND OVERNIGHT. SOME OF THESE COULD BE STRONG TO SEVERE.
THEREAFTER...THUNDERSTORM CHANCES CANNOT BE RULED OUT EACH DAY AS
THE LOWER ATMOSPHERE REMAINS MOIST AND UNSTABLE WITH SHORTWAVE
ENERGY CONTINUING TO TRAVERSE THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 105 PM CDT FRI AUG 23 2013
AT 1 PM CDT...A WARM FRONT ACROSS EASTERN MONTANA IS FORECAST TO
MOVE INTO WESTERN NORTH DAKOTA TONIGHT. THE FRONT WILL BE THE
FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS. AHEAD OF THIS FRONT
SOUTHEAST FLOW WILL BRING 15 TO 25 KT WINDS INTO CENTRAL NORTH
DAKOTA. THIS WINDS WILL DIMINISH TO LESS THAN 10 KTS TONIGHT AND
SATURDAY. DUE TO UNCERTAINTY IN THE TIMING AND AREA OF WIDELY
SCATTERED THUNDERSTORMS...HANDLED THE THREAT USING THE VICINITY
OPTION FOR THUNDERSTORMS...MAINLY BETWEEN 02Z-12Z TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
953 AM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 937 AM CDT FRI AUG 23 2013
WARM H500 RIDGE REMAINS OVER THE NORTHERN PLAINS TODAY. WITHIN THE
RIDGE THERE IS A WEAK VORT LOBE MOVING THROUGH WHICH...AIDED BY THE
DIURNAL LOW LEVEL JET...(30 KTS ON 12Z KBIS SOUNDING) SPONSORING
SOME WEAK CONVECTION CROSS THE SOUTH CENTRAL THIS MORNING.
CONVECTION EXPECTED TO DIMINISH AS THE LOW LEVEL FEATURES MIX OUT
THIS AM. THEN SYNOPTIC SCALE FORCING WILL PREVAIL THIS AFTERNOON
AND EVENING AS WARM FRONT IN EASTERN MONTANA MOVES EAST. THE WARM
FRONT WILL BE THE FOCUS FOR SCATTERED THUNDERSTORMS SOUTHWEST AND
WEST CENTRAL THIS AFTERNOON/EVENING. MADE SOME CHANGES TO CLOUDS
AND POPS THIS AM TO FOCUS ON THE ON GONG CONVECTION. OTHERWISE NO
OTHER CHANGES.
UPDATE ISSUED AT 643 AM CDT FRI AUG 23 2013
WEAK SHORTWAVE OVER SOUTHWEST NORTH DAKOTA IS PRODUCING ISOLATED
SHOWERS AND A FEW RUMBLES OF THUNDER OVER CENTRAL NORTH DAKOTA.
HAVE UPDATED POPS TO LATEST RADAR IMAGERY AND TRANSLATED THIS
NORTH AND EAST THROUGH MID MORNING. ALSO KEPT ISOLATED THUNDER
EXTENDING BACK INTO THE SOUTHWEST AS ANOTHER CELL HAD DEVELOPED
OVER THE FAR SOUTHWEST. OTHERWISE NO CHANGES TO THE CURRENT
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST CHALLENGE TODAY/TONIGHT WILL BE THUNDERSTORM
POTENTIAL AND AREAL COVERAGE.
LATEST WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL HIGH LOCATED OVER
SOUTHWEST KANSAS WITH RIDGING NORTH INTO EASTERN MONTANA. LOW
PRESSURE CIRCULATING OVER WESTERN OREGON IS EJECTING SEVERAL
SHORTWAVES INTO AND OVER THE RIDGE . THE 00Z MODEL GUIDANCE AND
HIGH RESOLUTION MODELS ALL OFFER DIFFERENT SCENARIOS FOR
CONVECTION TODAY INTO FRIDAY NIGHT. HIGHEST CONFIDENCE IS IN THE
NEAR TERM PERIOD WITH AN AREA OF SHOWERS AND THUNDERSTORMS IN
SOUTHEAST MONTANA MARCHING TOWARD SOUTHWEST NORTH DAKOTA. THE
LATEST HRRR HAS INITIALIZED WELL WITH THIS AREA AND WILL FOLLOW IT
FOR THE MORNING HOURS. ESSENTIALLY THIS AREA IS FORECAST TO SLIDE
ACROSS SOUTHWEST NORTH DAKOTA...THEN WEAKEN AND FALL APART AS IT
APPROACHES SOUTH CENTRAL NORTH DAKOTA LATER THIS MORNING. THE SHORTWAVE
CAUSING THIS PRECIPITATION IS SEEN OVER FAR SOUTHERN MONTANA NEAR
AND ALONG THE WYOMING BORDER. IT IS FORECAST TO CONTINUE TO PUSH
INTO SOUTHERN NORTH DAKOTA THIS AFTERNOON. VARIOUS CAPE/CIN
SOUNDINGS PROFILES PER NAM/GFS ARGUES FOR A MODEL BLEND AT THIS
TIME...AS IT IS UNCLEAR HOW MUCH OF A CAP REMAINS THIS AFTERNOON
INTO FRIDAY NIGHT. IT SEEMS REASONABLE THAT WITH A LEE SIDE
TROUGH IN EASTERN MONTANA TODAY...THIS WOULD BE THE AREA TO WATCH
FOR THE MOST INTENSE THUNDERSTORMS TO DEVELOP THIS AFTERNOON...WITH
CLOSE MONITORING THROUGH THE EVENING HOURS AS THEY MOVE NORTHEAST
INTO WESTERN NORTH DAKOTA. CURRENT THINKING IS ANY CONVECTION IN
CENTRAL NORTH DAKOTA THIS AFTERNOON SHOULD REMAIN ISOLATED IN
NATURE. H85 TEMPS WILL BE RISING AGAIN IN THE WEST WITH STRONG
WARM AIR ADVECTION RESULTING IN HIGHS IN THE LOW TO MID 90S.
FOR FRIDAY NIGHT...IT APPEARS THE MAIN FOCUS AND THREAT FOR SHOWERS
AND THUNDERSTORMS WILL RESIDE OVER NORTHERN NORTH DAKOTA. A SHORTWAVE
IS FORECAST TO MOVE ACROSS NORTHEAST MONTANA BY 06Z SATURDAY...AND
INTO SOUTHEASTERN SASKATCHEWAN BY 12Z SATURDAY. BEST FORCING IS IN
THE NORTH AND HAVE HIGH CHANCE POPS FORECAST OVERNIGHT WITH SLIGHT
CHANCE ELSEWHERE. OVERNIGHT LOWS WILL BE IN THE 60S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES...POSSIBLE HEAT ADVISORY HIGHLIGHTS AND PERIODIC
THUNDERSTORM CHANCES.
THERE IS A CONTINUED AGREEMENT IN THE MEAN UPPER LEVEL FLOW WHICH
FEATURES A STRONG RIDGE OVER THE CENTRAL U.S. THIS WILL RESULT IN
TEMPERATURES WELL ABOVE NORMAL THROUGH THE EXTENDED PERIOD ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. DAYTIME HIGHS FROM THE UPPER 80S
TO LOWER 90S NORTH AND LOWER TO MID 90S SOUTH ARE EXPECTED...WITH
SOME UPPER 90S AND LOWER 100 DEGREE READINGS QUITE POSSIBLE ACROSS
THE SOUTH. WITH DEWPOINTS GENERALLY IN THE 60S EACH DAY...AFTERNOON
HEAT INDICES WILL LIKELY APPROACH 100 DEGREES EACH DAY...ESPECIALLY
ACROSS THE SOUTH.
EVEN IN THE SHORT TERM MODELS ARE HAVING A HARD TIME RESOLVING
SHORTWAVES TRANSLATING THROUGH THE BROAD SOUTHWEST FLOW FROM THE
WESTERN UPPER LOW INTO THE NORTHERN PLAINS AND SOUTHERN CANADA.
THEREFORE A MODEL BLEND WAS UTILIZED FOR POPS THROUGH THE PERIOD.
MODELS ARE TRYING TO DEVELOP CONVECTION ON SATURDAY AND SATURDAY
NIGHT AS THERE WILL BE A SURFACE TROUGH TRACKING SLOWLY EAST ACROSS
THE AREA THAT IS PROGGED TO BE OVER CENTRAL NORTH DAKOTA BY 00 UTC
SUNDAY...WITH SHORTWAVE ENERGY MOVING INTO WESTERN NORTH DAKOTA. WE
WILL HAVE ABUNDANT CAPE OVER THE AREA SATURDAY AFTERNOON BUT WILL
LIKELY REMAIN CAPPED UNTIL SHORTWAVE ENERGY ARRIVES LATE IN THE DAY.
THUS THE BEST THUNDERSTORM CHANCES ON SATURDAY ARE EXPECTED TO BE IN
THE EVENING AND OVERNIGHT. SOME OF THESE COULD BE STRONG TO SEVERE.
THEREAFTER...THUNDERSTORM CHANCES CANNOT BE RULED OUT EACH DAY AS
THE LOWER ATMOSPHERE REMAINS MOIST AND UNSTABLE WITH SHORTWAVE
ENERGY CONTINUING TO TRAVERSE THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 937 AM CDT FRI AUG 23 2013
AT 9 AM CDT...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WERE ACROSS
SOUTH CENTRAL NORTH DAKOTA IMPACTING KBIS. THUNDERSTORM HAZARD
WILL BE TREATED WITH A VCTS (VICINITY) FORECAST FOR THUNDERSTORMS
THROUGH 17Z. OTHERWISE...A WARM FRONT IN EASTERN MONTANA WILL MOVE
SLOWLY EAST THIS AFTERNOON AND TONIGHT, THE WARM FRONT WILL BE THE
FOCUS FOR SCATTERED TO WIDELY SCATTERED THUNDERSTORMS THIS
AFTERNOON AND NIGHT AT KISN-KDIK-KBIS-KJMS. DUE TO UNCERTAINTY WILL
KEEP THE VCTS FOR THIS SITES. VFR AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
643 AM CDT FRI AUG 23 2013
.UPDATE...
ISSUED AT 643 AM CDT FRI AUG 23 2013
WEAK SHORTWAVE OVER SOUTHWEST NORTH DAKOTA IS PRODUCING ISOLATED
SHOWERS AND A FEW RUMBLES OF THUNDER OVER CENTRAL NORTH DAKOTA.
HAVE UPDATED POPS TO LATEST RADAR IMAGERY AND TRANSLATED THIS
NORTH AND EAST THROUGH MID MORNING. ALSO KEPT ISOLATED THUNDER
EXTENDING BACK INTO THE SOUTHWEST AS ANOTHER CELL HAD DEVELOPED
OVER THE FAR SOUTHWEST. OTHERWISE NO CHANGES TO THE CURRENT
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST CHALLENGE TODAY/TONIGHT WILL BE THUNDERSTORM
POTENTIAL AND AREAL COVERAGE.
LATEST WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL HIGH LOCATED OVER
SOUTHWEST KANSAS WITH RIDGING NORTH INTO EASTERN MONTANA. LOW
PRESSURE CIRCULATING OVER WESTERN OREGON IS EJECTING SEVERAL
SHORTWAVES INTO AND OVER THE RIDGE . THE 00Z MODEL GUIDANCE AND
HIGH RESOLUTION MODELS ALL OFFER DIFFERENT SCENARIOS FOR
CONVECTION TODAY INTO FRIDAY NIGHT. HIGHEST CONFIDENCE IS IN THE
NEAR TERM PERIOD WITH AN AREA OF SHOWERS AND THUNDERSTORMS IN
SOUTHEAST MONTANA MARCHING TOWARD SOUTHWEST NORTH DAKOTA. THE
LATEST HRRR HAS INITIALIZED WELL WITH THIS AREA AND WILL FOLLOW IT
FOR THE MORNING HOURS. ESSENTIALLY THIS AREA IS FORECAST TO SLIDE
ACROSS SOUTHWEST NORTH DAKOTA...THEN WEAKEN AND FALL APART AS IT
APPROACHES SOUTH CENTRAL NORTH DAKOTA LATER THIS MORNING. THE SHORTWAVE
CAUSING THIS PRECIPITATION IS SEEN OVER FAR SOUTHERN MONTANA NEAR
AND ALONG THE WYOMING BORDER. IT IS FORECAST TO CONTINUE TO PUSH
INTO SOUTHERN NORTH DAKOTA THIS AFTERNOON. VARIOUS CAPE/CIN
SOUNDINGS PROFILES PER NAM/GFS ARGUES FOR A MODEL BLEND AT THIS
TIME...AS IT IS UNCLEAR HOW MUCH OF A CAP REMAINS THIS AFTERNOON
INTO FRIDAY NIGHT. IT SEEMS REASONABLE THAT WITH A LEE SIDE
TROUGH IN EASTERN MONTANA TODAY...THIS WOULD BE THE AREA TO WATCH
FOR THE MOST INTENSE THUNDERSTORMS TO DEVELOP THIS AFTERNOON...WITH
CLOSE MONITORING THROUGH THE EVENING HOURS AS THEY MOVE NORTHEAST
INTO WESTERN NORTH DAKOTA. CURRENT THINKING IS ANY CONVECTION IN
CENTRAL NORTH DAKOTA THIS AFTERNOON SHOULD REMAIN ISOLATED IN
NATURE. H85 TEMPS WILL BE RISING AGAIN IN THE WEST WITH STRONG
WARM AIR ADVECTION RESULTING IN HIGHS IN THE LOW TO MID 90S.
FOR FRIDAY NIGHT...IT APPEARS THE MAIN FOCUS AND THREAT FOR SHOWERS
AND THUNDERSTORMS WILL RESIDE OVER NORTHERN NORTH DAKOTA. A SHORTWAVE
IS FORECAST TO MOVE ACROSS NORTHEAST MONTANA BY 06Z SATURDAY...AND
INTO SOUTHEASTERN SASKATCHEWAN BY 12Z SATURDAY. BEST FORCING IS IN
THE NORTH AND HAVE HIGH CHANCE POPS FORECAST OVERNIGHT WITH SLIGHT
CHANCE ELSEWHERE. OVERNIGHT LOWS WILL BE IN THE 60S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 AM CDT FRI AUG 23 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES...POSSIBLE HEAT ADVISORY HIGHLIGHTS AND PERIODIC
THUNDERSTORM CHANCES.
THERE IS A CONTINUED AGREEMENT IN THE MEAN UPPER LEVEL FLOW WHICH
FEATURES A STRONG RIDGE OVER THE CENTRAL U.S. THIS WILL RESULT IN
TEMPERATURES WELL ABOVE NORMAL THROUGH THE EXTENDED PERIOD ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. DAYTIME HIGHS FROM THE UPPER 80S
TO LOWER 90S NORTH AND LOWER TO MID 90S SOUTH ARE EXPECTED...WITH
SOME UPPER 90S AND LOWER 100 DEGREE READINGS QUITE POSSIBLE ACROSS
THE SOUTH. WITH DEWPOINTS GENERALLY IN THE 60S EACH DAY...AFTERNOON
HEAT INDICES WILL LIKELY APPROACH 100 DEGREES EACH DAY...ESPECIALLY
ACROSS THE SOUTH.
EVEN IN THE SHORT TERM MODELS ARE HAVING A HARD TIME RESOLVING
SHORTWAVES TRANSLATING THROUGH THE BROAD SOUTHWEST FLOW FROM THE
WESTERN UPPER LOW INTO THE NORTHERN PLAINS AND SOUTHERN CANADA.
THEREFORE A MODEL BLEND WAS UTILIZED FOR POPS THROUGH THE PERIOD.
MODELS ARE TRYING TO DEVELOP CONVECTION ON SATURDAY AND SATURDAY
NIGHT AS THERE WILL BE A SURFACE TROUGH TRACKING SLOWLY EAST ACROSS
THE AREA THAT IS PROGGED TO BE OVER CENTRAL NORTH DAKOTA BY 00 UTC
SUNDAY...WITH SHORTWAVE ENERGY MOVING INTO WESTERN NORTH DAKOTA. WE
WILL HAVE ABUNDANT CAPE OVER THE AREA SATURDAY AFTERNOON BUT WILL
LIKELY REMAIN CAPPED UNTIL SHORTWAVE ENERGY ARRIVES LATE IN THE DAY.
THUS THE BEST THUNDERSTORM CHANCES ON SATURDAY ARE EXPECTED TO BE IN
THE EVENING AND OVERNIGHT. SOME OF THESE COULD BE STRONG TO SEVERE.
THEREAFTER...THUNDERSTORM CHANCES CANNOT BE RULED OUT EACH DAY AS
THE LOWER ATMOSPHERE REMAINS MOIST AND UNSTABLE WITH SHORTWAVE
ENERGY CONTINUING TO TRAVERSE THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI AUG 23 2013
THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW SCT/BKN
LOW VFR CIGS AT KBIS/KJMS WITH MID/HIGH LEVEL CLOUDS ELSEWHERE.
LOCAL RADAR WAS INDICATING A LINE OF VERY LIGHT SHOWERS APPROACHING
KBIS AND THIS MIGHT MAKE IT INTO KJMS BY MID TO LATE
MORNING...OTHERWISE EXPECT SCT/BKN VFR CIGS WITH A CHANCE FOR
SHOWERS AND THUNDERSTORMS THROUGH THE TAF PERIOD. UNCERTAINTY
CONTINUES IN REGARDS TO WHERE THE THUNDERSTORMS WILL INITIATE AND
THEIR AREAL COVERAGE. THUS HAVE MAINTAINED A VCTS AT THOSE
AERODROMES FROM THE PREVIOUS TAF ISSUANCE...AND WILL CONTINUE TO
MONITOR FOR THUNDERSTORM DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1158 PM CDT SAT AUG 24 2013
.UPDATE...
06Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
KCLL/KUTS/KCXO...SHOULD HAVE VFR CIGS TONIGHT WITH MAYBE AN HOUR
OR SO OF 5SM AT KCXO IN THE MORNING BUT WILL NOT MENTION IN TAF.
CONVECTION WILL BE MAIN ISSUE TOMORROW AS TROPICAL WAVE MOVES
INLAND SLOWLY. MAY SEE A FEW SHOWERS A KCXO BUT THINK MAJORITY OF
CONVECTION STAYS SOUTH OF THESE TERMINALS. OVERALL NOT MUCH CHANGE
FROM THE 00Z TAF THINKING.
KIAH/KHOU/KSGR...EXPECT VFR CIGS TONIGHT BUT INCREASING CLOUDS
THROUGH THE MORNING. MAIN ISSUE WILL BE THE ONSET OF CONVECTION
WITH TROPICAL WAVE MOVING INLAND. TROPICAL MOISTURE MAY BE SLOW TO
MOVE INLAND SO THINK KIAH WILL BE ON EDGE OF CONVECTION. LOOKS
LIKE THE 00Z MODEL RUNS ARE IN LINE WITH CURRENT TAF THINKING. DID
TWEAK TIMING A BIT AND ADDED VCTS FOR KSGR/KHOU FOR EARLY
AFTERNOON HOURS. ALSO INCREASED WIND FOR AFTERNOON AS PRESSURE
GRADIENT TIGHTENS.
KLBX/KGLS...MAIN ISSUE WILL BE SHRA DEVELOPING IN THE MORNING AND
MOVING INLAND AS TROPICAL WAVE MOVES INLAND. WILL START VCSH AT
09Z FOR BOTH TERMINALS THEN DEVELOPING VCTS BY 15Z WITH MORE
DAYTIME HEATING AND INCREASED TROPICAL MOISTURE. THINK THERE COULD
BE A GOOD PERIOD OF SCT TSRA FOR BOTH TERMINALS FROM 15-21Z. FOR
NOW WILL LEAVE VCTS GIVEN SCT NATURE OF CONVECTION. POSSIBLE TO
TEMPO TSRA WITH APPROACHING CONVECTIVE CELLS.
39
&&
.PREV DISCUSSION... /ISSUED 1004 PM CDT SAT AUG 24 2013/
UPDATE...
POPS AND WEATHER GRIDS FOR TONIGHT AND SUNDAY.
DISCUSSION...
EQUIPMENT ISSUE OF NOTE...THE GALVESTON TEMPERATURE IS TOO COOL.
TECHNICIANS WILL CHECK OUT THE EQUIPMENT SOMETIME DURING THE NEXT
24 TO 48 HOURS.
00Z ANALYSIS AND MODEL FORECASTS PLACE THE EASTERLY WAVE OVER THE
NORTHERN GULF ALONG THE LA COAST INTO THE CENTRAL GULF OF MEXICO.
BOTH THE RAP AND NAM12 700 TO 300 MEAN LAYER FORECAST SHOWS THAT A
SMALLER LOW PRESSURE TROUGH WILL APPROACH THE UPPER TEXAS COAST
OVERNIGHT TONIGHT WITH THE MAIN WAVE THEN MOVING TO ALONG THE
COAST DURING THE MID MORNING SUNDAY. BOTH MODELS KEEP THE BEST
LAYER MOISTURE AND LIFT ALONG THE INTERSTATE 10 CORRIDOR SOUTH
DURING THE MIDDAY AND AFTERNOON PERIOD. THE RIDGE TO THE NORTH MAY
BE TOO MUCH FOR THE WAVE TO OVERCOME. EXPECT THE MAIN BULK OF THE
RAIN CHANCES WILL OCCUR ALONG AND EAST OF THE WAVE AXIS...AND
THERE MAY WELL BE A FAIRLY BIG DISCONTINUITY BETWEEN NO TO
ISOLATED COVERAGE AND BE BULK OF THE ACTIVITY. FOR THAT REASON
WILL ADJUST THE POPS DOWNWARD OVER THE INLAND AREAS TONIGHT AND
FROM THE INTERSTATE 10 CORRIDOR NORTHWARD ON SUNDAY. ADJUSTED THE
POPS SLIGHTLY DOWNWARD ELSEWHERE AS WELL BOTH PERIODS.
40
PREV DISCUSSION... /ISSUED 642 PM CDT SAT AUG 24 2013/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
KCLL/KUTS/KCXO...OVER SHOULD HAVE VFR CIGS WITH MAYBE AN HOUR OR
SO OF 5SM AT KCXO IN THE MORNING BUT WILL NOT MENTION IN TAF.
CONVECTION WILL BE MAIN ISSUE TOMORROW AS TROPICAL WAVE MOVES
INLAND SLOWLY. MAY SEE A FEW SHOWERS A KCXO BUT THINK MAJORITY OF
CONVECTION STAYS SOUTH OF THESE TERMINALS.
KIAH/KHOU/KSGR...EXPECT VFR CIGS TONIGHT BUT INCREASING CLOUDS
THROUGH THE MORNING. MAIN ISSUE WILL BE THE ONSET OF CONVECTION
WITH TROPICAL WAVE MOVING INLAND. TROPICAL MOISTURE MAY BE SLOW TO
MOVE INLAND SO THINK KIAH WILL BE ON EDGE OF CONVECTION. WILL
MENTION VCSH FOR ALL TAFS STARTING EARLIER IN THE DAY FOR
KHOU/KSGR AND IN THE AFTERNOON FOR KIAH. WILL NEED TO EVALUATE
VCTS FOR KHOU/KSGR FOR 17Z-20Z TIME FRAME FOR 06Z TAFS BASED ON
00Z MODEL RUNS. RIGHT NOW MORE CONFIDENT IN TS FOR KHOU/KSGR THAN
KIAH. THINK 00Z MODEL RUNS WILL GIVE BETTER IDEA. ALSO INCREASED
WIND FOR AFTERNOON AS PRESSURE GRADIENT TIGHTENS.
KLBX/KGLS...MAIN ISSUE WILL BE SHRA DEVELOPING IN THE MORNING AND
MOVING INLAND AS TROPICAL WAVE MOVES INLAND. WILL START VCSH AT
09Z FOR BOTH TERMINALS THEN DEVELOPING VCTS BY 15Z WITH MORE
DAYTIME HEATING AND INCREASED TROPICAL MOISTURE. THINK THERE COULD
BE A GOOD PERIOD OF SCT TSRA FOR BOTH TERMINALS FROM 15-21Z. WILL
HOLD OFF ON TEMPO TSRA AND USE 00Z MODELS TO EVALUATE IF THERE
WILL BE A TIME FRAME FOR MORE PRONOUNCED TSRA.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 75 94 74 / 10 30 20 40 20
HOUSTON (IAH) 77 92 75 91 75 / 10 40 40 50 20
GALVESTON (GLS) 79 87 79 87 80 / 30 50 60 60 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 AM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1111 PM CDT SAT AUG 24 2013
BUFKIT SOUNDINGS CONTINUE TO POINT TO AN INCREASING LOW LEVEL JET
THIS EVENING...WITH ABOUT 45 KTS BY 1500-2000 FT THROUGH 12-13Z OR
SO. SEE CONFIRMATION OF THIS IN RECENT VAD/PROFILER WINDS. WILL
CONTINUE THE MENTION OF LLWS IN THE TAFS AS A RESULT.
TIGHT PRESSURE GRADIENT PERSISTS INTO SUNDAY NIGHT...WITH LATE
MORNING/AFTERNOON MIXING RESULTING IN SOME HIGHER GUSTS. CONDITIONS
WILL STAY VFR WITH ONLY A FEW HIGH CLOUDS.
SUNDAY NIGHT...A SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS
SOUTHERN CANADA...BUT LAY A WEST-EAST RUNNING SFC FRONT OVER THE
REGION. INTERACTION WITH THE LOW LEVEL JET AND SOME INSTABILITY WILL
RESULT IN SHRA/TS ALONG AND NORTH OF THE BOUNDARY...WHICH THE MODELS
SUGGEST WILL SINK SOUTH OVERNIGHT...POTENTIALLY IMPACTING KRST/KLSE.
THIS TREND HAS BEEN RATHER CONSISTENT IN THE NAM/GFS/ECMWF OVER
THEIR PAST FEW RUNS...BUT NOT SURE HOW FAR SOUTH THIS PCPN WILL MAKE
IT BEFORE A WEAKENING LOW LEVEL JET RESULTS IN A DECREASE IN AREAL
COVERAGE. CLOUDS WILL BE ON THE INCREASE...BUT NORTH-SOUTH RUNNING
X-SECTIONS AND SOUNDINGS KEEP ANY CIGS VFR.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ017-029-032>034-041>044-053>055-061.
MN...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-086>088-094>096.
IA...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1105 AM EDT SUN AUG 25 2013
.LATE MORNING UPDATE...
OVERALL CLOUD COVER IS A BIT MORE ROBUST THAN ORIGINALLY EXPECTED
THANKS IN PART TO CONVECTIVE BLOW-OFF FROM ALL THE STORMS
OFFSHORE THIS MORNING. HAVE LOWERED HIGH TEMPS A COUPLE OF DEGREES
TO ACCOUNT FOR THE PARTIAL LOSS OF INSOLATION DURING THESE PEAK
HEATING HOURS. THE WEAKER HEATING MAY ALSO HAVE A NEGATIVE IMPACT ON
THE STRENGTH OF THE SEA-BREEZE. UPPER 80S WATER TEMPS AND UPPER 80S
TEMPS DON`T LEAD TO MUCH OF A DISCONTINUITY. WILL HAVE TO SEE JUST
HOW ANY LOSS OF SEA-BREEZE STRENGTH WILL IMPACT THE AFTERNOON
CONVECTION. SURE THERE ARE STILL PLENTY OF RESIDUAL BOUNDARIES OUT
THERE FROM ALL THE ACTIVITY THE PAST FEW DAYS TO GET SOME ACTIVITY
GOING...BUT THE LOSS OR WEAKNESS OF THIS MAIN MECHANISM WOULD LIKELY
HAVE A NEGATIVE IMPACT ON THE FOCUS FOR RISING MOTION. AT THE VERY
LEAST WOULD EXPECT A TEMPORAL DELAY IN GOOD CONVECTIVE COVERAGE
COMPARED TO PREVIOUS DAYS.
&&
.MID MORNING UPDATE (REST OF TODAY THROUGH MONDAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE CENTRAL AND
EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A LARGE AND
AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST NEAR AND
JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER DOWNSTREAM...
LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD WITH A WEAK
EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST TOWARD THE
FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF MID/HIGH LEVEL
MOISTURE IN PLACE OVER THE PENINSULA TODAY...BUT AN AREA OF MUCH
DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN OVER THE
CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP WILL MAKE A PUSH INTO
NORTHERN FLORIDA LATER TODAY...BUT GLOBAL GUIDANCE AGREES ON A MORE
SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING TONIGHT AND
MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE DEEPER MOISTURE AND
ALONG WITH INCREASING ANTI-CYCLONIC FLOW ALOFT/DEEP LAYER
SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES BACK DOWN TO CLIMO
NORMS...OR LESS...FOR THE EARLY PORTION OF THE UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
REST OF TODAY...WELL DEFINED LAND BREEZE AIDED BY THE SYNOPTIC E/NE
FLOW IS RESULTING IN PLENTY OF LOW LEVEL CONVERGENCE OFFSHORE THIS
MORNING. THIS CONVERGENCE ALONG WITH THE DEEP MOISTURE AND WEAK
SYNOPTIC SUPPORT FOR LIFT OVERHEAD IS MAKING FOR AN ACTIVE MORNING
IN TERMS OF THUNDERSTORMS AWAY FROM THE COAST. MARINERS STAYING
CLOSE TO THE COAST THIS MORNING SHOULD BE OK...BUT ANYONE PLANNING
TO GO FURTHER OFFSHORE BEYOND 15-20 MILES SHOULD EXPECT THE
OCCASIONAL ROUGHER WEATHER. THIS ACTIVITY WILL WEAKEN/DIMINISH
SOMEWHAT INTO THE AFTERNOON AS THE LAND-BREEZE COLLAPSES.
HOWEVER...DUE TO THE FAVORABLE ENVIRONMENT ALOFT...PROB WILL NOT
COMPLETELY DISAPPEAR AS OFTEN HAPPENS IN THE SUMMER.
BIT OF A DIFFICULT FORECAST PATTERN FOR THE LAND ZONES...ESPECIALLY
FOR THOSE AREA NORTH OF TAMPA BAY. LESS FAVORABLE ATMOSPHERIC
CONDITIONS TO SUPPORT NUMEROUS STORMS WILL BE SLIDING SOUTH TOWARD
THE AREA DURING THE DAY...BUT IT IS BE A CLOSE CALL WHETHER IT
ARRIVES IN TIME THIS AFTERNOON TO REALLY MAKE AN IMPACT FOR PLACES
LIKE LEVY/CITRUS/SUMTER/HERNANDO. THERE CERTAINLY WILL BE A DECREASE
IN DEEP MOISTURE FOR THESE AREA BY LATE IN THE DAY...HOWEVER THESE
MOISTURE/PW GRADIENTS CAN ALSO BE THE FOCUS FOR CONVECTIVE ACTIVITY.
WITH THIS IN MIND...WILL NOT GET TOO DETAILED WITH THE FORECAST AND
KEEP CHANCE POP WORDING NORTH OF TAMPA BAY...AND LIKELY POP WORDING
FURTHER SOUTH WITHIN THE ZONE OF DEEPEST MOISTURE AND UPPER LEVEL
TROUGH SUPPORT.
MID-LEVEL LAPSE RATES ARE NOTHING IMPRESSIVE TODAY WHICH SHOULD KEEP
THE CHANCES FOR SEVERE STORMS GENERALLY DOWN. HOWEVER...ONCE AGAIN
THE CONCERN WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINS OVER
SATURATED SOILS DUE TO WEAK WIND FIELDS AND RESULTING SLOW STORM
MOTION. WE DO HAVE SOME STRONGER FLOW TOWARD THE TOP OF THE TROP
TODAY...BUT ONLY THE TALLEST OF STORMS WILL REALLY BE ABLE TO FEEL
THIS IMPACT...WITH THE MAJORITY OF THE STORMS MASS COLUMN DEVELOPING
WITHIN A WEAK FLOW PATTERN.
EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE AFTER MIDNIGHT LEAVING
THE LAND ZONES GENERALLY DRY AFTER 02-03Z. THE LESS FAVORABLE
CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH MAY KEEP THE BEST
OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY LATE TONIGHT INTO
MONDAY MORNING COMPARED TO TODAY...AND THIS SEEMS TO BE A THEME IN
MANY OF THE LARGER SCALE PARAMETRIZED GUIDANCE.
MONDAY...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE
Q-VECTOR DIVERGENCE OVERHEAD FOR MUCH OF THE REGION TOMORROW
WHICH WILL WORK AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING.
WILL BE CURIOUS TO SEE WHAT KIND OF POPS COME OUT WITH THE 12Z
PACKAGE...BUT CAN NOT SEE GOING ANY HIGHER THAN WHAT IS CURRENTLY IN
THE GRIDS. GIVEN THE FORECAST ATMOSPHERIC COLUMN...A MORE CLIMO
CHANCE POP (40-50%) TYPE STORM COVERAGE CAN BE EXPECTED SOUTH OF
I-4...AND BELOW CLIMO (20-30%) POP COVERAGE FURTHER NORTH THROUGH
THE NATURE COAST.
ENJOY YOUR SUNDAY!
&&
.AVIATION...
LOW CIGS AND PATCHY BR AVOIDED THE TAF TERMINALS THIS MORNING.
OTHERWISE EXPECT VFR UNTIL THIS AFTERNOON WHEN VCNTY SHRA/TSRA FORM
DURING A 19Z-02Z WINDOW...WITH SOME TEMPO MVFR/LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE A NE FLOW THAT KEEPS
THE AFTERNOON SEA BREEZE CLOSE TO THE COAST.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE WELL TO OUR NORTH ALONG THE
MID-ATLANTIC STATES WILL PROVIDE AN EASTERLY WIND FLOW THROUGH THE
EARLY NEXT WEEK. THE GRADIENT IS EXPECTED TO RELAX ENOUGH THIS
AFTERNOON TO PROVIDE FOR AN ONSHORE SEA BREEZE TO DEVELOP. THE RIDGE
TO OUR NORTH WILL TAKE A POSITION BY TONIGHT AND MONDAY NIGHT TO
PROVIDE ENHANCED EASTERLY FLOW EACH NIGHT INTO THE EARLY MORNING
HOURS. WINDS MAY AT TIMES APPROACH CAUTIONARY LEVELS...ESPECIALLY TO
THE NORTH OF TARPON SPRINGS.
&&
.FIRE WEATHER...
NO CONCERNS OVERALL. SOME PATCHY GROUND FOG IS POSSIBLE AROUND
SUNRISE EACH DAY IN NORMALLY FOG-PRONE AREAS AND THOSE THAT
RECEIVE RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 90 75 / 60 40 30 30
FMY 89 73 88 72 / 60 40 60 20
GIF 90 72 90 72 / 60 30 40 30
SRQ 88 74 89 73 / 60 40 40 30
BKV 89 71 91 69 / 50 40 20 20
SPG 88 76 89 77 / 60 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
915 AM EDT SUN AUG 25 2013
.UPDATE (REST OF TODAY THROUGH MONDAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE CENTRAL AND
EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A LARGE AND
AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST NEAR AND
JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER DOWNSTREAM...
LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD WITH A WEAK
EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST TOWARD THE
FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF MID/HIGH LEVEL
MOISTURE IN PLACE OVER THE PENINSULA TODAY...BUT AN AREA OF MUCH
DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN OVER THE
CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP WILL MAKE A PUSH INTO
NORTHERN FLORIDA LATER TODAY...BUT GLOBAL GUIDANCE AGREES ON A MORE
SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING TONIGHT AND
MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE DEEPER MOISTURE AND
ALONG WITH INCREASING ANTI-CYCLONIC FLOW ALOFT/DEEP LAYER
SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES BACK DOWN TO CLIMO
NORMS...OR LESS...FOR THE EARLY PORTION OF THE UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
REST OF TODAY...WELL DEFINED LAND BREEZE AIDED BY THE SYNOPTIC E/NE
FLOW IS RESULTING IN PLENTY OF LOW LEVEL CONVERGENCE OFFSHORE THIS
MORNING. THIS CONVERGENCE ALONG WITH THE DEEP MOISTURE AND WEAK
SYNOPTIC SUPPORT FOR LIFT OVERHEAD IS MAKING FOR AN ACTIVE MORNING
IN TERMS OF THUNDERSTORMS AWAY FROM THE COAST. MARINERS STAYING
CLOSE TO THE COAST THIS MORNING SHOULD BE OK...BUT ANYONE PLANNING
TO GO FURTHER OFFSHORE BEYOND 15-20 MILES SHOULD EXPECT THE
OCCASIONAL ROUGHER WEATHER. THIS ACTIVITY WILL WEAKEN/DIMINISH
SOMEWHAT INTO THE AFTERNOON AS THE LAND-BREEZE COLLAPSES.
HOWEVER...DUE TO THE FAVORABLE ENVIRONMENT ALOFT...PROB WILL NOT
COMPLETELY DISAPPEAR AS OFTEN HAPPENS IN THE SUMMER.
BIT OF A DIFFICULT FORECAST PATTERN FOR THE LAND ZONES...ESPECIALLY
FOR THOSE AREA NORTH OF TAMPA BAY. LESS FAVORABLE ATMOSPHERIC
CONDITIONS TO SUPPORT NUMEROUS STORMS WILL BE SLIDING SOUTH TOWARD
THE AREA DURING THE DAY...BUT IT IS BE A CLOSE CALL WHETHER IT
ARRIVES IN TIME THIS AFTERNOON TO REALLY MAKE AN IMPACT FOR PLACES
LIKE LEVY/CITRUS/SUMTER/HERNANDO. THERE CERTAINLY WILL BE A DECREASE
IN DEEP MOISTURE FOR THESE AREA BY LATE IN THE DAY...HOWEVER THESE
MOISTURE/PW GRADIENTS CAN ALSO BE THE FOCUS FOR CONVECTIVE ACTIVITY.
WITH THIS IN MIND...WILL NOT GET TOO DETAILED WITH THE FORECAST AND
KEEP CHANCE POP WORDING NORTH OF TAMPA BAY...AND LIKELY POP WORDING
FURTHER SOUTH WITHIN THE ZONE OF DEEPEST MOISTURE AND UPPER LEVEL
TROUGH SUPPORT.
MID-LEVEL LAPSE RATES ARE NOTHING IMPRESSIVE TODAY WHICH SHOULD KEEP
THE CHANCES FOR SEVERE STORMS GENERALLY DOWN. HOWEVER...ONCE AGAIN
THE CONCERN WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINS OVER
SATURATED SOILS DUE TO WEAK WIND FIELDS AND RESULTING SLOW STORM
MOTION. WE DO HAVE SOME STRONGER FLOW TOWARD THE TOP OF THE TROP
TODAY...BUT ONLY THE TALLEST OF STORMS WILL REALLY BE ABLE TO FEEL
THIS IMPACT...WITH THE MAJORITY OF THE STORMS MASS COLUMN DEVELOPING
WITHIN A WEAK FLOW PATTERN.
EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE AFTER MIDNIGHT LEAVING
THE LAND ZONES GENERALLY DRY AFTER 02-03Z. THE LESS FAVORABLE
CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH MAY KEEP THE BEST
OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY LATE TONIGHT INTO
MONDAY MORNING COMPARED TO TODAY...AND THIS SEEMS TO BE A THEME IN
MANY OF THE LARGER SCALE PARAMETRIZED GUIDANCE.
MONDAY...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE
Q-VECTOR DIVERGENCE OVERHEAD FOR MUCH OF THE REGION TOMORROW
WHICH WILL WORK AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING.
WILL BE CURIOUS TO SEE WHAT KIND OF POPS COME OUT WITH THE 12Z
PACKAGE...BUT CAN NOT SEE GOING ANY HIGHER THAN WHAT IS CURRENTLY IN
THE GRIDS. GIVEN THE FORECAST ATMOSPHERIC COLUMN...A MORE CLIMO
CHANCE POP (40-50%) TYPE STORM COVERAGE CAN BE EXPECTED SOUTH OF
I-4...AND BELOW CLIMO (20-30%) POP COVERAGE FURTHER NORTH THROUGH
THE NATURE COAST.
ENJOY YOUR SUNDAY!
&&
.AVIATION...
LOW CIGS AND PATCHY BR AVOIDED THE TAF TERMINALS THIS MORNING.
OTHERWISE EXPECT VFR UNTIL THIS AFTERNOON WHEN VCNTY SHRA/TSRA FORM
DURING A 19Z-02Z WINDOW...WITH SOME TEMPO MVFR/LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE A NE FLOW THAT KEEPS
THE AFTERNOON SEA BREEZE CLOSE TO THE COAST.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE WELL TO OUR NORTH ALONG THE
MID-ATLANTIC STATES WILL PROVIDE AN EASTERLY WIND FLOW THROUGH THE
EARLY NEXT WEEK. THE GRADIENT IS EXPECTED TO RELAX ENOUGH THIS
AFTERNOON TO PROVIDE FOR AN ONSHORE SEA BREEZE TO DEVELOP. THE RIDGE
TO OUR NORTH WILL TAKE A POSITION BY TONIGHT AND MONDAY NIGHT TO
PROVIDE ENHANCED EASTERLY FLOW EACH NIGHT INTO THE EARLY MORNING
HOURS. WINDS MAY AT TIMES APPROACH CAUTIONARY LEVELS...ESPECIALLY TO
THE NORTH OF TARPON SPRINGS.
&&
.FIRE WEATHER...
NO CONCERNS OVERALL. SOME PATCHY GROUND FOG IS POSSIBLE AROUND
SUNRISE EACH DAY IN NORMALLY FOG-PRONE AREAS AND THOSE THAT
RECEIVE RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 90 75 / 60 40 30 30
FMY 89 73 88 72 / 60 40 60 20
GIF 90 72 90 72 / 60 30 40 30
SRQ 88 74 89 73 / 60 40 40 30
BKV 89 71 91 69 / 50 40 20 20
SPG 88 76 89 77 / 60 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
920 AM MDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 912 AM MDT SUN AUG 25 2013
DECREASED WINDS A FEW KNOTS FOR THIS AFTERNOON BASED ON WINDS
MIXING DOWN FROM 700MB WHERE THE TOP OF THE MIXED LAYER WILL BE.
SO FAR THE DAY LOOKS VERY SIMILAR TO YESTERDAY. AM A BIT CONCERNED
WITH THE MORE SOUTH-SOUTHWEST DIRECTION OF THE WINDS AS THIS MAY
ALLOW DEW POINTS TO FALL A FEW MORE DEGREES THAN YESTERDAY. SO FAR
LOOKS LIKE WINDS/RELATIVE HUMIDITIES WILL BE VERY CLOSE TO MEETING
CRITICAL FIRE WEATHER CONDITIONS. AT THIS TIME...AND BASED ON WHAT
HAPPENED YESTERDAY...DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY
FIRE WEATHER PRODUCTS FOR THE AFTERNOON. THE RECENT RAINS ALSO ADD
MORE COMPLEXITY TO WHERE THE FUELS WILL BE FAVORABLE FOR RAPID
FIRE GROWTH AND WHERE THEY WONT BE. AT THIS POINT CHEYENNE TO
RAWLINS AND SHERMAN TO THOMAS COUNTIES AND RED WILLOW COUNTY LOOK
TO BE THE MOST FAVORABLE FOR CRITICAL FIRE WEATHER CONDITIONS.
WILL CONTINUE TO MONITOR IN CASE A FIRE WEATHER PRODUCT IS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 529 AM MDT SUN AUG 25 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK...WITH ONLY PASSING HIGH CLOUDS. BREEZY CONDITIONS WILL
REDEVELOP THIS MORNING AND CONTINUE THROUGH AT LEAST THE EARLY
EVENING HOURS...POSSIBLY INTO THE OVERNIGHT AS TIGHT PRESSURE
GRADIENT REMAINS IN PLACE. STRONGEST WIND GUSTS WILL BE THIS
AFTERNOON WHEN GUSTS 30-35KT WILL BE POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
531 AM MDT SUN AUG 25 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 529 AM MDT SUN AUG 25 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK...WITH ONLY PASSING HIGH CLOUDS. BREEZY CONDITIONS WILL
REDEVELOP THIS MORNING AND CONTINUE THROUGH AT LEAST THE EARLY
EVENING HOURS...POSSIBLY INTO THE OVERNIGHT AS TIGHT PRESSURE
GRADIENT REMAINS IN PLACE. STRONGEST WIND GUSTS WILL BE THIS
AFTERNOON WHEN GUSTS 30-35KT WILL BE POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
729 AM CDT SUN AUG 25 2013
.AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
&&
.PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. IT WILL BE HUMID WITH DEWPOINTS IN THE
UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY THE
SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE
WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
AVIATION...CANNON
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
642 AM CDT SUN AUG 25 2013
.AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
&&
.PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS DULUTH MN
604 AM CDT SUN AUG 25 2013
.UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
AVIATION...06Z TAF ISSUANCE.
VFR CONDITIONS WILL PREVAIL MOST OF THE FCST PERIOD EXCEPT IN THE
NRN TIER OF MN WHERE LOCAL MVFR/IFR MAY OCCUR IN LOWER CLOUD
DEVELOPMENT AND HEAVIER STORMS EARLY THIS MORNING. A WEAK SFC BDRY
WILL TRY TO PUSH SOUTH ACROSS THE AREA TODAY. MID LVL WARMTH
SHOULD MAKE CONVECTION TOUGH TO DEVELOP. AMENDMENTS MAY BE
REQUIRED GIVEN UNCERTAINTY OF CONVECTIVE DEVELOPMENT. LLWS AT
KBRD/KHYR AS 45/50KT LLJ TRANSLATES EAST THROUGH 12Z.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....CANNON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1001 AM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 1000 AM CDT SUN AUG 25 2013
WEAK HIGH PRESSURE PATTERN OVER THE STATE THIS MORNING WITH A WEAK
TROUGH OF LOW PRESSURE LINGERING ACROSS SOUTH CENTRAL AND
SOUTHEAST NORTH DAKOTA. THIS COULD BE THE FOCUS FOR AN ISOLATED
THUNDERSTORM THIS MORNING. WILL RE EVALUATE THE POTENTIAL FOR THE
AFTERNOON...FOR NOW LEFT A SLIGHT CHANCE THUNDERSTORMS SOUTHEAST
THIS MORNING WHERE HRRR MODEL GENERATES ISOLATED CONVECTION. ARE
OF CLOUDS IN CENTRAL/EASTERN MONTANA APPEAR TO BE ASSOCIATED WITH
A SHORT WAVE CENTERED IN WESTERN WYOMING MOVING NORTHEAST. THE
RIDGE MAY PREVENT THE CLOUDS AND SHOWERS/THUNDERSTORMS FROM MAKING
MUCH EASTWARD ADVANCEMENT INTO WESTERN NORTH DAKOTA THIS
AFTERNOON... ALTHOUGH NEW NAM GENERATES SOME THUNDERSTORMS AFTER 3
PM. DON`T HAVE ENOUGH CONFIDENCE TO MOVE UP THE TIME TABLE FORM
THIS EVENING INTO THE IS AFTERNOON.
UPDATE ISSUED AT 644 AM CDT SUN AUG 25 2013
MAINLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS
MORNING. HIGH PRESSURE OVER THE WEST WITH DRIER AIR WORKING INTO
THE AREA ALLOWED TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
50S. MEANWHILE A LOW PRESSURE TROUGH REMAINS FROM CENTRAL SOUTH
DAKOTA INTO EAST CENTRAL NORTH DAKOTA WITH MUCH HIGHER HUMIDITIES.
TEMPERATURES HERE HAVE ONLY FALLEN INTO THE UPPER 60S AND LOWER
70S. NO SIGNIFICANT CHANGES TO THE FORECAST THIS UPDATE. DID KEEP
A SLIGHT CHANCE OF THUNDER OVER THE SOUTHEAST NEAR THE WEAK
SURFACE TROUGH. LATEST 06 UTC NAM IS INDICATING LIGHT QPF ENTERING
INTO THE WEST LATER THIS AFTERNOON. WILL LEAVE THIS OUT OF THE
FORECAST FOR NOW BUT WILL LET THE DAY SHIFT MONITOR.
&&
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 303 AM CDT SUN AUG 25
2013
MAIN HIGHLIGHT IN THE SHORT TERM WILL BE ANOTHER HOT DAY WITH
HIGHS WELL INTO THE 90S...HOWEVER THUNDERSTORMS WILL BE CONFINED
TO FAR SOUTH CENTRAL NORTH DAKOTA AND THE SOUTHERN JAMES RIVER
VALLEY.
EARLY THIS MORNING...THE LATEST LOCAL RADAR SHOWS A LINE OF
SHOWERS AND THUNDERSTORMS INITIATING ALONG A FRONTAL BOUNDARY/LOW
CONVERGENCE ZONE...STRETCHING FROM CORSON COUNTY IN SOUTH DAKOTA
NORTHEAST BETWEEN BURLEIGH AND EMMONS COUNTY AND INTO STUTSMAN
COUNTY. WATER VAPOR INDICATIVE OF A SHORTWAVE MOVING THROUGH
CENTRAL NORTH DAKOTA EARLY THIS MORNING PROVIDING THE LIFT NEEDED
TO SUSTAIN AND REDEVELOP THE PRECIPITATION. A COUPLE OF THE
THUNDERSTORMS HAVE COME CLOSE TO SEVERE CRITERIA...AND WILL
CONTINUE TO MONITOR.
FOR TODAY...UPPER LEVEL RIDGING CENTERED OVER CENTRAL KANSAS
COMBINED WITH AN UPPER TROUGH ALONG THE WEST COAST...WILL MAINTAIN
A SOUTHWEST FLOW INTO NORTH DAKOTA. A COUPLE OF SHORTWAVES ARE
FORECAST TO SLIDE ACROSS THE NORTHERN BORDER WITH LITTLE OR NO
AFFECT IN TERMS OF PRECIPITATION. THE AFOREMENTIONED FRONTAL
BOUNDARY IS FORECAST TO SHIFT A BIT FURTHER SOUTH TODAY...INTO
NORTHERN SOUTH DAKOTA. HOWEVER A SHORTWAVE MOVING OUT FROM
COLORADO IS FORECAST TO MOVE INTO CENTRAL SOUTH DAKOTA THIS
AFTERNOON. THIS SHOULD LEAD TO ISOLATED THUNDERSTORMS IN OUR
SOUTHEAST ZONES CLOSEST TO THE FRONT. ELSEWHERE EXPECT MOSTLY
SUNNY...DRY..AND HOT CONDITIONS WITH HIGHS 90F TO 98F. HEAT
INDICES ARE FORECAST IN THE MID TO UPPER 90S IN OUR SOUTH CENTRAL
ZONES AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER
OUTLOOK.
FOR SUNDAY NIGHT...LEE SIDE TROUGH DEVELOPS IN SOUTHEAST MONTANA
AS A COUPLE OF SHORTWAVES ARRIVE VIA THE SOUTHWEST FLOW INTO
WESTERN NORTH DAKOTA. HAVE MENTIONED ISOLATED THUNDERSTORMS WEST
SUNDAY NIGHT WITH DRY CONDITIONS CENTRAL. LOWS WILL AGAIN BE IN
THE 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 303 AM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE
WHICH WILL CONTINUE TO INDICATE VERY WARM DAYTIME HIGH TEMPERATURES.
SOUTHERN PORTIONS OF THE CWA COULD FLIRT WITH HEAT ADVISORY
CRITERIA ON MONDAY AND AGAIN LATER IN THE WEEK. IN ADDITION...
ALMOST DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES
EVERY DAY BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY THE ECMWF/GEM APPEAR
STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND BRING QPF ACROSS
THE NORTH. THE SOUTH WILL LIKELY REMAIN CAPPED UNDER WARM MID
LEVEL TEMPERATURES. THE GFS IS STRONGER WITH THE RIDGING OVER THE
AREA AND KEEPS PRECIPITATION MAINLY NORTH OF THE BORDER.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
FRIDAY BUT TIMING AND PLACEMENT DIFFERENCES INCREASE WITH LESS
CONSENSUS BETWEEN THE MODELS EXISTS THAN THE MODEL RUNS FROM 24
HOURS AGO. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED SOLUTION
FOR PRECIPITATION. MODELS DO INDICATE AT LEAST A TEMPORARY
BREAKDOWN OF THE UPPER RIDGE LATE IN THE PERIOD WITH THE ECMWF A
GOOD 18 TO 24 HOURS QUICKER TO BRING PRECIPITATION CHANCES AND
COOLER TEMPERATURES TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 1000 AM CDT SUN AUG 25 2013
AT 9 AM CDT...WEAK REGION OF HIGH PRESSURE COVERED NORTH DAKOTA.
SKIES WERE CLEAR AND VFR CONDITIONS PREVAILED. LITTLE WILL CHANGE
TODAY AS VFR IS EXPECTED TO CONTINUE. SCATTERED SHOWERS AND
THUNDERSTORMS ARE FORECAST TO MOVE INTO WESTERN NORTH DAKOTA LATE
THIS EVENING AND OVERNIGHT. SOME THUNDERSTORMS MAY IMPACT KISN-
KDIK AFTER 08Z/3 AM USING THE VCTS TO DESCRIBE THE THREAT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS TULSA OK
904 AM CDT SUN AUG 25 2013
.DISCUSSION...
ANOTHER HOT AND HUMID DAY IS IN STORE FOR EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS WITH MID/UPPER RIDGING IN CONTROL. 12Z UPPER
AIR DATA INDICATES 500MB HEIGHTS ARE RISING AND SOME 700MB
MOISTURE REMAINS AT LITTLE ROCK...SHREVEPORT AND FORT WORTH. THIS
WOULD SUGGEST THE BEST POTENTIAL FOR ISOLATED AFTERNOON
SHOWERS/STORMS WILL BE OVER THE HIGH TERRAIN OF SOUTHEAST OKLAHOMA
AND/OR WEST CENTRAL ARKANSAS AND DOWN NEAR THE RED RIVER. COVERAGE
OF PRECIP YESTERDAY WAS VERY LOW...AND WITH THE RISING UPPER
HEIGHTS THAT WILL LIKELY NOT CHANGE TODAY. THE LATEST HRRR SHOWS
HINTS OF ISOLATED DEVELOPMENT DOWN IN THAT REGION. WILL ELECT TO
CARRY SILENT 10 POPS THERE...AND WILL MONITOR THE CU FIELD LATER
TODAY TO SEE IF AN INCREASE IS WARRANTED IN SPOTS.
LACY
&&
.PREV DISCUSSION... /ISSUED 320 AM CDT SUN AUG 25 2013/
DISCUSSION...
A LARGE UPPER RIDGE WILL REMAIN PARKED OVER THE AREA THROUGH THE
ENTIRE FORECAST PERIOD. THE GFS IS QUICKER THAN THE ECMWF TO BEGIN
TO BREAK DOWN THE RIDGE NEXT WEEKEND INTO THE FIRST WEEK OF
SEPTEMBER WHICH IS A REVERSAL FROM MODEL RUNS A COUPLE DAYS AGO.
IN THE MEANTIME...HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN WILL
PREVAIL. TEMPERATURES WILL SLOWLY INCH UP LATER THIS WEEK...LIKELY
PEAKING ON FRIDAY OR SATURDAY. STAYED CLOSE TO GUIDANCE
TEMPERATURES THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 94 74 94 72 / 0 0 0 0
FSM 94 73 94 71 / 10 0 0 0
MLC 94 73 94 71 / 10 10 10 0
BVO 93 69 93 67 / 0 0 0 0
FYV 91 67 91 65 / 10 0 0 0
BYV 91 68 91 66 / 0 0 0 0
MKO 93 72 93 70 / 0 0 0 0
MIO 91 71 91 69 / 0 0 0 0
F10 93 73 93 71 / 0 0 0 0
HHW 96 73 96 71 / 10 10 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
653 AM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...THROUGH TONIGHT
ISSUED AT 650 AM CDT SUN AUG 25 2013
THE LOW LEVEL WIND SHEAR AT KLSE WILL DISSIPATE BY 25.14Z AS
DIURNAL MIXING OCCURS AND NOCTURNAL JET WEAKENS. WITH WINDS
ALREADY GUSTING INTO THE 25 KNOT RANGE AT KRST...TOOK THE LOW
LEVEL WIND SHEER OUT OF THE TAF AT 12Z.
FROM 25.14Z THROUGH 26.02Z...THE SOUTHWEST WINDS WILL GUST INTO
THE 20 TO 30 KNOT RANGE.
FOR LATE TONIGHT...THE MAIN QUESTION IS WHETHER A THUNDERSTORM
COMPLEX WILL MOVE SOUTH TO THE INTERSTATE 90 CORRIDOR. BOTH THE
NAM AND GFS SUGGEST THAT THIS WILL BE POSSIBILITY. MEANWHILE THE
GEM AND ECMWF SUGGEST THAT IT WILL STAY NORTH OF THE AREA. WITH
THIS UNCERTAINTY JUST ADDED A VCTS AFTER 26.09Z AT BOTH TAF SITES.
IF THESE STORMS DO MOVE INTO THE AREA...THERE WILL BE A
POSSIBILITY THAT THEY COULD PRODUCE WIND DAMAGE AND LARGE HAIL.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ017-029-032>034-041>044-053>055-061.
MN...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-086>088-094>096.
IA...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...AJ
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 500 AM CDT SUN AUG 25 2013
UPPER RIDGE CONTINUES TO FLATTEN OVER THE WESTERN GREAT LAKES AS
SHORT WAVE IMPULSE MOVES EAST ACROSS NORTHERN LAKE SUPERIOR THIS
MORNING. FOR THE MOST PART...SHORT RANGE MODELS INCLUDING THE HRRR
AND RAP DID A RATHER LOUSY JOB HANDLING STRONGER CONVECTION NORTH
OF WISCONSIN...AS WELL AS LIGHTER SCATTERED SHOWER ACTIVITY MOVING
ACROSS CENTRAL AND NORTHERN WISCONSIN EARLY THIS MORNING. SCATTERED
SHOWER AND ISOLATED THUNDERSHOWER ACTIVITY OVER THE FORECAST AREA
APPEARS TO BE ASSOCIATED WITH VERY WEAK UPPER-LEVEL IMPULSE...MODEST
WAA AND NEAR EASTERN EDGE OF ROBUST CAP EXTENDING FROM CENTRAL
MINNESOTA INTO NORTHWEST WISCONSIN. THIS ACTIVITY WILL CONTINUE TO
PUSH ACROSS THE FORECAST AREA THIS MORNING AND SHOULD REMAIN
SCATTERED AND LIGHT IN INTENSITY. ACTIVITY EXPECTED TO BE EAST OF
THE FORECAST AREA BY AROUND 15Z.
LOOKING FARTHER UPSTREAM...MORE SCATTERED THUNDERSTORM ACTIVITY
HAS DEVELOPED OVER WESTERN MINNESOTA AHEAD OF FRONTAL BOUNDARY
OVER THE DAKOTAS. MAJORITY OF THE GUIDANCE SUGGESTS THAT THIS
ACTIVITY WILL BEGIN TO SINK MORE SSE ACROSS CENTRAL MINNESOTA
LATER THIS MORNING AND GRADUALLY WEAKEN AS IT CONTINUES TO
PROPAGATE AWAY FROM FRONTAL BOUNDARY. HOWEVER LATEST RADAR TRENDS
SHOWING MORE OF AN EASTWARD MOVEMENT AND IF THIS ACTIVITY HOLDS
TOGETHER IT MAY IMPACT THE NORTHWEST PORTION OF THE FORECAST AREA
LATE THIS MORNING. WILL NEED TO KEEP AN EYE ON THIS ACTIVITY THIS
MORNING. FOR NOW WILL STICK TO CURRENT THINKING THAT THIS
ACTIVITY SHOULD WEAKEN BEFORE IT REACHES THE FORECAST AREA. THUS
IT APPEARS THAT FORECAST AREA STILL ON TRACK FOR A HOT AND
INCREASINGLY HUMID DAY. DID NOT MAKE ANY CHANGES TO PREVIOUS MAX
TEMPERATURE FORECAST FOR TODAY THUS STILL EXPECT TEMPS TO REACH
THE 90-95 DEGREE RANGE OVER THE WESTERN PORTION OF THE FORECAST
AREA WITH READINGS NEAR 90 ACROSS THE NORTHWOODS. DID ADJUST
DEWPOINTS DOWN A DEGREE OR TWO THIS AFTERNOON WITH ANTICIPATED
AFTERNOON MIXING. THUS HEAT INDICES WILL BE GENERALLY IN 95 TO 100
DEGREE RANGE WITH HIGHEST VALUES OVER THE WESTERN PORTION OF THE
FORECAST AREA THIS AFTERNOON.
FOR THIS EVENING AND TONIGHT...QUESTION THEN BECOMES WHEN AND
WHERE THUNDERSTORM ACTIVITY WILL FIRE AS SHORTWAVE IMPULSE HEADS
EAST TOWARD THE WESTERN GREAT LAKES AND FRONTAL BOUNDARY
APPROACHES. ALTHOUGH THERE HAS BEEN A VARIETY OF SOLUTIONS AS TO
HOW THE SCENARIO WILL PLAY OUT...SEEMS THAT A WEAK CONSENSUS OF
THE GUIDANCE SUGGESTS THAT THUNDERSTORM ACTIVITY WILL DEVELOP NEAR
THE WISCONSIN-MICHIGAN BORDER...ALONG AND AHEAD OF FRONTAL
BOUNDARY FORECAST TO DRIFT SSE INTO NORTHERN WISCONSIN THIS
EVENING. THIS BOUNDARY MAY ALSO GET SOME REINFORCEMENT FROM LAKE
SUPERIOR BREEZE. THIS ACTIVITY SHOULD THEN SAG SOUTHWARD ACROSS
THE FORECAST AREA OVERNIGHT INTO MONDAY MORNING. SHOULD BE PLENTY
OF INSTABILITY OVER THE FORECAST AREA SUNDAY EVENING WITH MLCAPES
AROUND 3000 J/KG. BEST DEEP LAYER SHEAR TO SUSTAIN UPDRAFTS WILL
BE OVER THE NORTHERN HALF OF THE FORECAST AREA. SPC ADDED MOST
OF THE FORECAST AREA INTO A SLIGHT RISK FOR SEVERE LATE THIS
AFTERNOON AND INTO THE LATE EVENING HOURS WHICH SEEMS REASONABLE.
PRIMARY THREAT APPEARS TO BE DAMAGING WINDS AND PERHAPS SOME
LARGE HAIL. MODELS VARY AS TO THE TIMING THE CONVECTION WILL
FIRE...BEST GUESS IS SOMETIME IN THE 23-02Z TIME FRAME WITH
ACTIVITY MOVING SOUTH OR SOUTHEAST ACROSS THE FORECAST AREA TOWARD
MIDNIGHT. WILL ALSO NEED TO KEEP AN EYE ON A LOCALLY HEAVY
RAINFALL THREAT...ESPECIALLY IF ACTIVITY CAN TRAIN FROM WEST TO
EAST ALONG FRONTAL BOUNDARY LATER TONIGHT.
MORE UNCERTAINTY FOR MONDAY AS MODELS DIVERGE ON HOW LONG ACTIVITY
WILL PERSIST ALONG FRONTAL BOUNDARY EXPECTED TO BE LOCATED
SOMEWHERE OVER NORTHERN WISCONSIN. LOCATION OF RESIDUAL
THUNDERSTORM OUTFLOW IS ALSO A FACTOR AS TO WHERE ADDITIONAL
CONVECTION MAY FIRE AGAIN DURING THE DAY ON MONDAY. FOR NOW KEPT
BROAD BRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST AREA. MAX TEMPS
ON MONDAY WILL BE DEPENDENT ON RESIDUAL CLOUD
COVER...PRECIPITATION AND LOCATION OF FRONTAL BOUNDARY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 501 AM CDT SUN AUG 25 2013
WHILE THE CNTRL CONUS UPR RDG TO REMAIN THE MAIN WEATHER FEATURE
THRU MUCH OF THE UPCOMING WEEK...ITS SLOW RETROGRESSION FROM THE
MID-MS VALLEY TO THE CNTRL HI PLAINS WL ALLOW THE MEAN FLOW TO
TURN NW BY THU AND BRING SLIGHTLY COOLER/DRIER CONDITIONS TO NE
WI. MAIN FCST EMPHASIS TO BE THRU MID-WEEK AS A FRONTAL BOUNDARY
MOVES THRU AN UNSTABLE AIR MASS AND SETS THE STAGE FOR TSTMS. A
FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH LOCALLY HEAVY
RAINFALL. TEMPS TO REMAIN WELL ABOVE NORMAL TIL FURTHER NOTICE...
ESPECIALLY THRU THU.
PLENTY OF QUESTIONS LINGER FOR TUE STARTING WITH WHERE (IF) MON
NGT`S CONVECTION TO BE LOCATED...WHERE THE NRN WI FRONTAL BOUNDARY
TO RESIDE...WL ADDITIONAL PCPN DEVELOP ON THE EDGE OF THE CAP AND
COULD ANY OF THESE STORMS TURN SEVERE? THE KEY APPEARS TO BE THE
MON NGT CONVECTION SINCE IF IT WERE TO DEVELOP...MORE CLOUDS AND
BRIEF STABILIZATION WOULD OCCUR. IF THIS CONVECTION STAYS TO THE
NORTH...THIS WOULD ALLOW TEMPS TO SOAR ONCE AGAIN AND ALLOW THE
ATMOSPHERE TO REALLY DESTABILIZE BY THE AFTERNOON. TO TOP ALL OF
THIS OFF...THE MDLS BRING A WEAK SFC TROF INTO WI. HARD TO FATHOM
NOT SEEING ANY PCPN MON NGT...THUS HAVE SIDED WITH MENTIONING A
HIGHER POP ON TUE ACROSS FAR NE WI WHERE THE WEAKER CAP WL EXIST.
SEVERE POTENTIAL TO BE DICTATED BY HOW WARM WE CAN GET AND WHETHER
THAT APPROACHING WEAK SFC TROF CAN GENERATE ENUF LIFT TO BREAK THE
CAP. IF THE CAP IS BROKEN...WE COULD SEE A ROUND OF STRONG TO
SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS AND TORRENTIAL
DOWNPOURS.
SHWR/TSTM THREAT WOULD CARRYOVER INTO TUE EVENING UNTIL THE SFC
TROF EXITS THE AREA AND A WEAK AREA OF HI PRES BEGINS TO BUILD
ACROSS THE UPR MS VALLEY. ONLY CHANGE TO THIS PART OF THE FCST WAS
TO FOCUS PCPN CHCS TO THE EVENING WITH A CLEARING TREND FOR THE
OVRNGT HOURS. BY THE MIDDLE OF THE WEEK...THE UPR RDG IS PROGGED
TO HAVE RETROGRADED BACK TOWARD THE CNTRL PLAINS WTH THE MEAN FLOW
OVER THE GREAT LAKES TURNING MORE NW. WEAK HI PRES TO BE SITUATED
OVER THE WRN GREAT LAKES REGION ON WED...THUS A DECENT AMOUNT OF
SUNSHINE IS ANTICIPATED. 8H TEMPS TO STILL BE AROUND +20C...SO
TEMPS WL REMAIN RATHER WARM WITH A MINOR DROP IN DEW POINTS BEHIND
THE DEPARTED SFC TROF.
THERE ARE NOW CONCERNS FOR THU`S DRY FCST AS THE MDLS ARE
INDICATING THE NEXT MID-LEVEL SHORTWAVE TROF TO BE ROUNDING THE
CNTRL CONUS UPR RDG AND DIVING SE TOWARD WI. NOT SURE AT THIS
POINT WHETHER THIS POTENTIAL CONVECTION WOULD IMPACT ALL OF NE WI
OR DIVE SE ENUF TO ONLY AFFECT CNTRL WI. AT THIS POINT...FOLLOWED
THE CONSENSUS SOLUTION WHICH BRINGS A SLIGHT CHC POP TO MUCH OF
THE FCST AREA. TEMPS FOR WED LOOK TO BE SIMILAR TO WED WITH PLENTY
OF 80S TO GO AROUND.
ANOTHER AREA OF HI PRES IS EXPECTED TO BUILD SWD FROM CANADA
DURING THE THU NGT/FRI TIME PERIOD. DO NOT CARE FOR THE MINIMAL
POP ADVERTISED BY THE CONSENSUS SOLUTION AND PREFER TO GO DRY FOR
FRI WITH TEMPS GENERALLY IN THE 80-85 DEG RANGE. RETURN FLOW THEN
SETS UP OVER THE REGION NEXT WEEKEND WHICH WL LEAD TO WARMER
TEMPS...AN UPTICK IN HUMIDITY LEVELS AND THE POSSIBILITY OF WAA-
INDUCED PCPN CHCS. ATTM...ANY PCPN APPEARS TO BE WIDELY SCT AT
BEST WITH NO FOCUSING MECHANISM PRESENT.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 501 AM CDT SUN AUG 25 2013
GENERALLY VFR CONDITIONS TODAY. SCATTERED THUNDERSTORM ACTIVITY
WILL BEGIN TO SPREAD FROM NORTHWEST TO SOUTHEAST ACROSS THE
FORECAST AREA TONIGHT...HOWEVER CONFIDENCE LOW AS TO WHEN
CONVECTION WILL FIRE THIS EVENING AND HOW FAR SOUTH IT WILL
PROPAGATE OVERNIGHT. BEST CHANCE FOR MVFR CONDITIONS ASSOCIATED WITH
SCATTERED THUNDERSTORM ACTIVITY WILL BE AT NORTHERN TAF SITES AFTER
03Z.
.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......KALLAS
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
340 PM EDT SUN AUG 25 2013
.SYNOPSIS...19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE
CENTRAL AND EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A
LARGE AND AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST
NEAR AND JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER
DOWNSTREAM... LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD
WITH A WEAK EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST
TOWARD THE FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF
MID/HIGH LEVEL MOISTURE IN PLACE OVER THE PENINSULA...BUT AN AREA OF
MUCH DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN
OVER THE CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP IS CURRENTLY MAKING
A VERY SLOW PUSH INTO NORTHERN FLORIDA...BUT GLOBAL GUIDANCE AGREES
ON A MORE SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING
LATER TONIGHT AND MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE
DEEPER MOISTURE AND ALONG WITH INCREASING ANTI-CYCLONIC FLOW
ALOFT/DEEP LAYER SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES
BACK DOWN TO CLIMO NORMS...OR LESS...FOR THE EARLY PORTION OF THE
UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
&&
.SHORT TERM (TONIGHT THROUGH TUESDAY)...
LEFTOVER MID/LATE EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE
AFTER MIDNIGHT LEAVING THE LAND ZONES GENERALLY DRY AFTER 02-03Z.
THE LESS FAVORABLE CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH
MAY KEEP THE BEST OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY
LATE TONIGHT INTO MONDAY MORNING...AND THIS CONTINUES TO BE A THEME
IN MANY OF THE LARGER SCALE PARAMETRIZED 12Z GUIDANCE.
MONDAY/MONDAY NIGHT...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE DEEP
LAYER Q-VECTOR DIVERGENCE OVER THE REGION TOMORROW...WHICH WILL WORK
AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING. GIVEN THE FORECAST
ATMOSPHERIC COLUMN...A MORE CLIMO CHANCE POP (40-50%) STORM COVERAGE
CAN BE EXPECTED SOUTH OF I-4. WAS ORIGINALLY THINKING ONLY ISOLATED
/ SLIGHT CHANCE POPS FOR THE NATURE COAST...HOWEVER LATEST GUIDANCE
HAS A BIT MORE ATLANTIC MOISTURE IN THE LOWER TROP GETTING INTO THE
MIX FOR THESE NORTHERN ZONES. THEREFORE WILL KEEP POPS IN THE CHANCE
RANGE 30-40% FOR THE NATURE COAST...HOWEVER SHOWERS OVER THESE
NORTHERN COUNTIES ARE LIKELY TO BE MORE SHALLOW AND BRIEF IN NATURE
/ LIFE CYCLE DUE TO THE DRIER AIR ALOFT. THIS SHOULD LIMIT THE
RAINFALL QPF POTENTIAL...WHICH IS GOOD NEWS FOR AREAS THAT NEED SOME
TIME TO DRY OUT FROM THE SIGNIFICANT RAINFALL OF THE PAST SEVERAL
DAYS.
EVEN THE LOWER LEVEL ATLANTIC MOISTURE LOOKS NOW TO BE SCOURED OUT
MONDAY NIGHT WHICH SHOULD LEAD TO A DRY OVERNIGHT PERIOD AFTER ANY
ISOLATED MID EVENING SHOWERS PUSH OFFSHORE / DIMINISH. THE DRIER
COLUMN AND CLEARING SKIES MAY ALSO ALLOW FOR SOME "COOLER"
OVERNIGHT LOWS BY DAWN. WOULD NOT BE SURPRISED TO SEE PORTIONS OF
THE NATURE COAST AND INLAND SOUTH-CENTRAL ZONES REACH THE UPPER
60S. BREAK OUT THE COATS!
TUESDAY...
THE DRIER COLUMN IS WELL ENTRENCHED FOR THE AFTERNOON. DURING THE
FORECAST PROCESS YESTERDAY...WAS CONCERNED WITH THE INFLUENCE OF AN
UPPER LOW THAT THE GFS WAS TRYING TO CLOSE OFF NEAR THE SW FLORIDA
COAST. LAST COUPLE OF GFS RUNS HAVE COME AROUND MORE TO THE ECMWF
SOLUTION...WHICH IS LATER AND LOCATED CLOSER TO THE BAHAMAS. THIS
TREND SUGGESTS THAT THIS FEATURE WILL HAVE LITTLE INFLUENCE ON OUR
LOCAL WEATHER THROUGH THE SHORT TERM PERIOD (IF EVER). WILL STILL
HAVE LIGHT EASTERLY FLOW ON TUESDAY WHICH GENERALLY IS FAVORABLE FOR
CONVECTION ALONG THE FL WEST COAST. HOWEVER...GIVEN THE DRY COLUMN
ALOFT AND GENERAL ANTI-CYCLONIC NATURE OF THE FLOW ALOFT...WILL KEEP
THE TYPICAL SPATIAL POP PATTERN FOR CONVECTION IN EASTERLY
FLOW...BUT DROP THE RAIN CHANCES DOWN CLOSER TO THE ECMWF MOS
GUIDANCE NUMBERS. DESPITE THE DRIER AIR...THE GFS MOS NUMBERS SEEM
TOO LOW FOR EASTERLY FLOW AND WILL DISREGARD FOR NOW.
AFTERNOON/EVENING RAIN CHANCES WILL FEATURE 30-40% SOUTH OF TAMPA
BAY...AND 20-30% FOR THE I-4 CORRIDOR NORTHWARD ALONG THE NATURE
COAST...WHERE THE PROXIMITY TO THE UPPER RIDGE WILL PROVIDE THE
GREATEST DEGREE OF SYNOPTIC SUPPRESSION.
&&
.LONG TERM (WEDNESDAY-SUNDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT SHOWING THE HIGH PRESSURE
RIDGE AXIS ACROSS NORTH FLORIDA TO START THE DAY WEDNESDAY...WITH
THE AXIS SHIFTING STEADILY SOUTHWARD INTO SOUTH FLORIDA BY FRIDAY
EVENING. THE RIDGE AXIS WILL REMAIN ACROSS SOUTH FLORIDA AND THE
FLORIDA STRAIGHTS OVER THE UPCOMING WEEKEND AS A TROUGH OF LOW
PRESSURE STALLS OUT ALONG THE NORTHERN GULF COAST. OVERALL...EXPECT
ISOLATED/SCATTERED MAINLY AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS WEDNESDAY THROUGH FRIDAY. SHOULD SEE AN INCREASE IN
SHOWER/THUNDERSTORM COVERAGE OVER THE UPCOMING WEEKEND AS DEEPER
MOISTURE ASSOCIATED WITH THE TROUGH OF LOW PRESSURE PUSHES SOUTHWARD
INTO THE AREA. TEMPERATURES ARE EXPECTED TO RUN CLOSE TO CLIMO
THROUGH THE LONG TERM PERIODS.
&&
.AVIATION...
BKN MID/HIGH CLOUDS THROUGH THE EVENING...WITH VCNTY TSRA UNTIL 02Z.
BETWEEN 21Z-00Z TEMPO MVFR VSBY/CIG IN TSRA WITH LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE AN E-NE
FLOW...KEEPING THE SEA BREEZE CLOSE TO THE COAST THIS
AFTERNOON...THROUGH MON.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE CURRENTLY CENTERED NEAR THE
MID-ATLANTIC STATES WILL SLOWLY WEAKEN AS IT SETTLES SOUTHWARD
TOWARD THE EASTERN GULF OF MEXICO DURING THE NEXT SEVERAL DAYS. THE
POSITION OF THIS RIDGE WILL BE FAVORABLE THE NEXT COUPLE OF NIGHTS
FOR ENHANCED EASTERLY FLOW THAT WILL LINGER INTO THE EARLY MORNING
HOURS. WINDS WILL BE STRONGEST AND POTENTIALLY APPROACH CAUTIONARY
LEVELS AT TIMES TO THE NORTH OF TARPON SPRINGS. BY MIDWEEK THE
RIDGE WILL APPROACH THE AREA ALLOW THE GRADIENT AND RESULTING WINDS
TO DIMINISH WELL BELOW HEADLINE CRITERIA.
&&
.FIRE WEATHER...
HIGH PRESSURE WELL TO OUR NORTH WILL SLOWLY SLIDE SOUTHWARD THROUGH
THE EARLY PORTION OF THE WEEK. DRIER AIR ALOFT WILL RESULT IN A MORE
TYPICAL DISTRIBUTION OF AFTERNOON AND EVENING STORMS THE NEXT
SEVERAL DAYS COMPARED TO THE WIDESPREAD ACTIVITY SEEN IN PAST DAYS.
DESPITE THE DRIER AIR ALOFT...NO SIGNIFICANT PUSH OF DRIER AIR IN
THE LOWER LEVELS IS EXPECTED AND RELATIVE HUMIDITY VALUES ARE
FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS. AT THIS TIME...NO
SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH THE MIDDLE
OF THE WEEK.
&&
.HYDROLOGY...
THE CYPRESS CREEK AT WORTHINGTON GARDENS IS THE ONLY RIVER CURRENTLY
EXPECTED TO REACH FLOOD STAGE. AS OF 3PM...WATER LEVEL IS AT 7.4
FEET WITH FLOOD STAGE REACHED AT 8 FEET. THE RIVER IS EXPECTED TO
REACH FLOOD STAGE LATE IN THE DAY ON MONDAY OR EARLY TUESDAY. WATER
LEVELS ON THE HORSE CREEK NEAR ARCADIA REMAIN HIGH...BUT THE RIVER
IS EXPECTED TO STAY JUST BELOW FLOOD STAGE OVER THE NEXT FEW DAYS.
HOWEVER ANY HEAVY PERSISTENT RAINFALL FROM AFTERNOON SHOWERS AND
THUNDERSTORMS OVER THESE BASINS COULD CAUSE WATER LEVELS TO RISE
MORE THAN CURRENTLY FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 90 75 91 / 30 40 20 30
FMY 74 90 73 91 / 30 50 30 40
GIF 72 91 72 92 / 20 40 20 30
SRQ 74 90 74 91 / 30 40 30 30
BKV 71 90 70 91 / 20 40 20 30
SPG 77 90 78 90 / 30 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM...JELSEMA
AVIATION...RUDE
HYDROLOGY...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1121 AM MDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 912 AM MDT SUN AUG 25 2013
DECREASED WINDS A FEW KNOTS FOR THIS AFTERNOON BASED ON WINDS
MIXING DOWN FROM 700MB WHERE THE TOP OF THE MIXED LAYER WILL BE.
SO FAR THE DAY LOOKS VERY SIMILAR TO YESTERDAY. AM A BIT CONCERNED
WITH THE MORE SOUTH-SOUTHWEST DIRECTION OF THE WINDS AS THIS MAY
ALLOW DEW POINTS TO FALL A FEW MORE DEGREES THAN YESTERDAY. SO FAR
LOOKS LIKE WINDS/RELATIVE HUMIDITIES WILL BE VERY CLOSE TO MEETING
CRITICAL FIRE WEATHER CONDITIONS. AT THIS TIME...AND BASED ON WHAT
HAPPENED YESTERDAY...DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY
FIRE WEATHER PRODUCTS FOR THE AFTERNOON. THE RECENT RAINS ALSO ADD
MORE COMPLEXITY TO WHERE THE FUELS WILL BE FAVORABLE FOR RAPID
FIRE GROWTH AND WHERE THEY WONT BE. AT THIS POINT CHEYENNE TO
RAWLINS AND SHERMAN TO THOMAS COUNTIES AND RED WILLOW COUNTY LOOK
TO BE THE MOST FAVORABLE FOR CRITICAL FIRE WEATHER CONDITIONS.
WILL CONTINUE TO MONITOR IN CASE A FIRE WEATHER PRODUCT IS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 25 2013
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. VERY SIMILAR CONDITIONS
IN PLAY TODAY COMPARED TO YESTERDAY. SOUTHERLY WINDS WILL REMAIN
GUSTY THROUGH THE AFTERNOON AND WELL INTO THE EVENING THEN RETURN
MID TO LATE MORNING MONDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GRAY ME
428 PM EDT SUN AUG 25 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT AND WILL
GRADUALLY CROSS THE REGION ON MONDAY FOLLOWED BY A WEAK COLD FRONT
MONDAY NIGHT. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA ON
TUESDAY. LOW PRESSURE WILL APPROACH FROM THE WEST TUESDAY NIGHT
AND WILL PASS SOUTH OF NEW ENGLAND ON WEDNESDAY. A TROUGH OF LOW
PRESSURE WILL LINGER OVER THE REGION ON THURSDAY AS LOW PRESSURE
SHIFTS EAST INTO THE MARITIMES. THE TROUGH WILL SLOWLY MOVE SOUTH
THROUGH THE REGION ON FRIDAY. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT DEW POINT AND TEMPERATURES
OBSERVATIONS. CLOUDS WILL ALSO BE ENTERING THE FORECAST AREA
SHORTLY FROM THE WEST...WITH THE LATEST HRRR RUN TIMING ANY SHOWER
ACTIVITY WILL OCCUR AFTER MIDNIGHT OVER WESTERN ZONES.
PREV DISC...
INCREASING CLOUDS TONIGHT AS A WARM FRONT APPROACHES FROM THE
WEST. CONVECTIVE COMPLEX MOVING THROUGH EASTERN ONTARIO WILL DIE
OUT OVER WESTERN NEW YORK LATER THIS AFTERNOON AND THIS EVENING
BUT A FEW SHOWERS WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA
GENERALLY AFTER MIDNIGHT. SHOULD SEE A MUCH WARMER NIGHT WITH LOWS
RANGING THROUGH THE 50S FROM NORTH TO SOUTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
ANY LINGERING SHOWERS WILL PUSH SOUTH OF THE REGION MONDAY MORNING
AND MUCH OF THE DAY NOW LOOKS DRY WITH VARIABLE MID LEVEL CLOUDS.
MAY BE ENOUGH INSTABILITY IN SOUTHERN NEW HAMPSHIRE TO POP OFF AN
AFTERNOON SHOWER OR THUNDERSTORM BUT APPEARS BEST CAPES REMAIN
SOUTH AND WEST OF THE FORECAST AREA. EXPECT HIGH FROM THE MID 70S
TO NEAR 80.
WEAK COLD FRONT WILL DROP SOUTH THROUGH THE REGION MONDAY NIGHT.
MAY BE ENOUGH TO POP OFF AN ISOLATED SHOWER OR THUNDERSTORM BUT NOT
LOOKING FOR ANY WIDESPREAD ACTIVITY. WILL BE ANOTHER MILD NIGHT
WITH LOWS IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE UPPER LEVEL TROF AND WEAK LOW/SFC WARM FRONT MOVE TO OUR E AND
SE BY 12Z TUESDAY ALLOWING WEAK HIGH PRESSURE UNDER AN UPPER LEVEL
RIDGE TO BUILD INTO THE REGION GIVING US FAIR AND VERY WARM WX FOR
TUESDAY INTO EARLY TUESDAY NIGHT. A BROAD LARGE SCALE UPPER LEVEL
RIDGE BUILDS OVER THE CENTRAL AND WRN U.S. ALLOWING A LONG WAVE TROF
TO CARVE OUT OVER THE ERN U.S. AS A SERIES OF WEAK UPPER LEVEL TROFS
MOVE INTO THE ERN U.S.
THIS WILL PROVIDE UNSETTLED WX FROM LATE TUESDAY NIGHT THRU
WEDNESDAY EVENING UNTIL A MORE ORGANIZED UPPER LEVEL TROF FORMS AND
FORCES LOW PRESSURE TO GAIN SOME STRENGTH WHILE MOVING FROM S OF THE
GULF OF MAINE OFF TO THE NE ON THURSDAY. DEPENDING ON HOW CLOSE THE
SFC LOW TRACKS WILL DETERMINE IF WE RECEIVE MORE ORGANIZED RAIN LATE
WEDNESDAY NIGHT THROUGH THURSDAY MORNING AND POSSIBLY INTO THE
AFTERNOON.
THE AXIS OF THE UPPER LEVEL TROF SHIFTS SLOWLY EAST BUT MAINTAINS A
CYCLONIC FLOW ALOFT THURSDAY NIGHT AND FRIDAY SO THAT SOME
INSTABILITY SHRA ARE POSSIBLE. GRADUALLY AN UPPER LEVEL RIDGE BUILDS
IN FRIDAY NIGHT AND SATURDAY ALLOWING HIGH PRESSURE TO APPROACH FROM
CANADA. THIS BRINGS DRIER AND COOLER WX FRIDAY NIGHT AND SATURDAY.
THE UPPER LEVEL RIDGE BREAKS DOWN AS A SHORT WAVE DRIVES EASTWARD
THRU THE RIDGE BRINGING WARMER AND MORE HUMID AIR /THUS INCREASING
INSTABILITY/ INTO THE REGION ALONG WITH ISOLD TO MAYBE SCT SHRA AND
TSTMS ON SUNDAY...EVEN THOUGH THE TROF IS WEAKENED AS IT MOVES THRU
THE UPPER LEVEL RIDGE AND THE ASSOCIATED WEAK SFC FRONT STAYS WELL
TO OUR NW.
GENERALLY USED BLEND OF GFS/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5
THEN A BLEND OF GFS40/GMOS/MEX FOR THE REST OF THE LONG TERM FCST.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...VFR TONIGHT THROUGH MONDAY. AREAS OF MVFR/IFR
CEILINGS MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...UNSETTLE WX LATE TUESDAY
NIGHT THRU THURSDAY AND POSSIBLY INTO FRIDAY WITH THE POTENTIAL
FOR MVFR/IFR CONDITIONS AT TIMES.
&&
.MARINE...
SHORT TERM...NO FLAGS.
LONG TERM /TUESDAY THROUGH FRIDAY/...WINDS AND SEAS EXPECTED TO
BE BELOW SCA CRITERIA DUE TO WEAK PRESSURE GRADIENT. HOWEVER...
PASSING LOW OUTSIDE OF THE COASTAL WATERS MAY STRENGTHEN ON
THURSDAY AND THURSDAY NIGHT THAT COULD PRODUCE CONDITIONS
APPROACHING SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
351 PM EDT SUN AUG 25 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 350 PM EDT SUN AUG 25 2013
A WARM FRONT WILL MOVE EAST OF THE AREA THIS EVENING PUTTING
SOUTHWEST MICHIGAN IN WARM AND HUMID AIR UNTIL THE COLD FRONT
COMES THROUGH WEDNESDAY MORNING. EXPECT PERIODS OF THUNDERSTORMS
FROM MONDAY AFTERNOON INTO WEDNESDAY MORNING. FOR MOST OF THE AREA
THE GREATEST RISK OF SIGNIFICANT RAINFALL IS TUESDAY INTO TUESDAY
NIGHT. WARM DRY WEATHER WILL THEN PREVAIL UNTIL THE NEXT WARM
FRONT COMES THROUGH NEXT WEEKEND. THAT COULD BE THE HOTTEST
WEATHER OF THE SUMMER.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 350 PM EDT SUN AUG 25 2013
WE ARE WATCHING TWO SIGNIFICANT FEATURES THIS AFTERNOON... FIRST IS
THE POTENTIAL FOR THUNDERSTORMS ONCE WE ARE SOLIDLY IN THE WARM
AND HUMID AIR... THEN THE SECOND ISSUE IS JUST HOW HOT IT GET THE
NEXT TWO AFTERNOONS.
FIRST THE CONVECTION ISSUE. IT NOW SEEMS THE FRONTAL BOUNDARY OVER
THE UPPER PENINSULA WILL NOT MAKE MUCH PROGRESS SOUTH TONIGHT SO I
DO NOT EXPECT THE CONVECTION ASSOCIATED WITH IT TO MAKE MUCH
PROGRESS EITHER. THIS IS SHOWN BY THE NSSL AND SPC WAF... AND THE
HRRR MODELS AS WELL AS THE RAP MODEL. WELL THE CONVECTION WILL
MOVE SOUTH FROM WHERE IT IS BUT IT SHOULD NOT GET MUCH FATHER
SOUTH THEN ROUTE 10 BY MORNING SO I HAVE LOW CHANCE POPS UP THERE.
THAT IS BASED ON THE LOW LEVEL JET AXIS NOT GETTING MUCH FARTHER
SOUTH THAN CAD/HTL BY 12Z. NOTE THAT THERE ARE TWO PRIMARY
SHORTWAVES DRIVING ALL OF THIS. THIS FIRST ONE IS MOVING EAST WITH
THE CONVECTION NORTHEAST OF LAKE HURON. THE SECOND IS LESS
OBVIOUS BUT IS CURRENTLY OVER THE DAKOTAS AND HEADING EAST OVER
THE TOP OF THE UPPER RIDGE. IT IS THAT SHORTWAVE THAT WILL SPARK
THE CONVECTION OVER NRN WI AND THE UPPER PENINSULA THIS EVENING
INTO THE OVERNIGHT HOURS. THAT CONVECTION WILL DRIVE THE COLD
FRONT SOUTH TONIGHT AND MAY BRING THUNDERSTORMS TO OUR NORTHERN
CWA BY SUNRISE.
THIS LEAD SHORTWAVE CREATES A SORT OF COLD FRONT /WARM FRONT SET
UP. SO THE COLD FRONT TRAILING THE LEAD SHORTWAVE IS WHAT DIVES
THE CONVECTION SOUTH TONIGHT INTO MONDAY. THEN THE NEXT UPSTREAM
WAVE PUSHES IT ALL BACK NORTH AS A WARM FRONT MONDAY NIGHT. THERE
IS AN UPPER LEVEL JET ASSOCIATED WITH THIS SO I WOULD EXPECT
ANOTHER ROUND OF CONVECTION MONDAY NIGHT INTO TUESDAY MORNING WITH
THAT. HOWEVER... IF THE COLD FRONT DOES NOT GET TOO FAR SOUTH
MONDAY... THEN MOST OF THE STORMS SHOULD WELL NORTH OF INTERSTATE
96 MONDAY NIGHT.
FINALLY THE SHORTWAVE OVER NV CURRENTLY CLIMBS THE UPPER RIDGE AND
DIVES DOWN THE FRONT SIDE OF IT TUESDAY AND THAT BRINGS A MORE
SIGNIFICANT COLD FRONT THROUGH THE AREA BY EARLY WEDNESDAY. IT IS
THAT NV SHORTWAVE THAT I BELIEVE WILL BRING OUR BEST SHOT FOR SIGNIFICANT
RAINFALL. THIS WILL LIKELY BE IN THE TUESDAY AFTERNOON INTO
TUESDAY NIGHT TIME FRAME. IT WOULD BE THEN THAT THERE WOULD BE THE
GREATEST RISK OF STRONG TO SEVERE STORMS. DEEP LAYER SHEAR IS IN
THE 30 TO 40 KNOT RANGE DURING THAT TIME AND MIX LAYER CAPES
AROUND 1500 J/KG. WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES
THERE IS LITTLE QUESTION IF WE GET THUNDERSTORMS MINOR FLOODING OF
AREAS WITH POOR DRAINAGE IS A REAL THREAT.
AS FOR HOW HOT IT WILL GET... THE 850 TEMPS ARE AROUND 21C MONDAY
AND TUESDAY. THAT WOULD SUPPORT HIGHS IN LOWER 90S FOR SURE. ALSO THE
1000/925 MB THICKNESS VALUES SUGGEST MID 90S ACTUALLY. THE ONLY
THING THAT WILL KEEP OUR TEMPERATURES FROM GETTING THAT WARM IS IF
THERE IS TO MUCH CONVECTIVE DEBRIS CLOUDS AROUND. WHICH IS A REAL
PROBLEM FOR THIS FORECAST AS THE COLD FRONT WILL COME CLOSE TO US
MONDAY AFTERNOON AND EARLY EVENING. MOS TEMP FORECASTS KEEP HIGHS IN
THE 80S BOTH DAY BUT GIVEN HOW WARM THE THICKNESS IS AND 850 TEMPS
I HAVE A REAL PROBLEM FORECASTING HIGHS SO LOW. SO WE HAVE TO WAIT
AND SEE JUST HOW MUCH CLOUDS GET GENERATED FROM THE UPSTREAM
CONVECTION TO SEE HOW HOT IT REALLY GETS THE NEXT TWO DAYS.
MEANWHILE I WILL GO WITH HIGHS IN THE LOWER 90S FOR NOW AND CALL
THAT GOOD.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN AUG 25 2013
THE GOING MID SUMMER-LIKE FORECAST AND MAINLY DRY CONDITIONS IN THE
LONG TERM CONTINUES TO LOOK ON TRACK.
WE CONTINUE TO EXPECT THAT THE FRONT SHOULD BE EXITING THE FCST AREA
TO THE SOUTH RIGHT AROUND 12Z WED. THIS OCCURS AS THE UPPER HEIGHTS
LOWER SLIGHTLY OVER THE AREA...AND NW FLOW ALOFT COMMENCES. THIS
WILL RESULT IN DRY CONDITIONS...TEMPS DROPPING A COUPLE OF DEGREES
AND SLIGHTLY LOWER HUMIDITY LEVELS AS WE COULD POTENTIALLY SEE ON
TUE. H850 TEMPS DROP TO AROUND 18-19C WHICH WOULD STILL SUPPORT
HIGHS IN THE MID 80S TO AROUND 90.
THE MODELS CONTINUE TO INDICATE SOME SORT OF MCS DEVELOPING TO OUR W
LATE THU AND MOVING SE ALONG THE UPPER RIDGE ON FRI. WE HAVE BETTER
CONFIDENCE AT THIS TIME THAT THIS COMPLEX WILL END UP SW OF THE AREA
CLOSER TO THE BETTER INSTABILITY SOUTH OF THE FRONT. VERY WARM AND
DRY CONDITIONS ARE EXPECTED ONCE AGAIN FOR FRI.
WE EXPECT TO SEE ANOTHER SURGE OF HEAT THEN BEGINNING NEXT WEEKEND.
WE WILL SEE THE UPPER RIDGE AXIS BUILD BACK OVER THE AREA BY NEXT
SUN AS SHORT WAVE ENERGY MOVING ACROSS CANADA WILL SHIFT IT E/SE.
INCREASING LOW LEVEL SW FLOW AHEAD OF THE SFC LOW WILL HELP TO
ADVECT THE HOT TEMPS OVER THE PLAINS OVER OUR AREA. H850 TEMPS ARE
FCST TO INCREASE TO THE LOWER 20S C BY NEXT SUN. WE COULD SEE MAX
TEMPS WELL INTO THE 90S IF THIS PLAYS OUT THIS WAY. WE HAVE GONE
SOMEWHAT CONSERVATIVE FOR NOW WITH HIGHS IN THE LOWER TO MID 90S.
THE TRANSITION OF THIS AIR MASS INTO THE AREA COULD BRING A LOW CHC
OF PCPN TO THE AREA ON SUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 126 PM EDT SUN AUG 25 2013
MAIN ITEMS OF CONCERN IN THE 18Z FCST CYCLE ARE CONVECTIVE CHCS LATE
IN THE PERIOD AND WIND GUST TRENDS.
THE ONLY CONCERN IN THE FIRST FEW HOURS OF THE 18Z FCSTS WILL BE
WIND GUSTS. STRONGER GRADIENT MOVING IN IS HELPING TO PRODUCE WIND
GUSTS AS HIGH AS 25 KNOTS THIS AFTERNOON. SOME HIGHER WINDS ARE IN
PLACE A COUPLE OF THOUSAND FEET UP DUE TO THE WARMER AIR ADVECTING
IN. WE EXPECT THE WIND GUSTS TO DIMINISH AROUND SUNSET TONIGHT OR
00-01Z. VFR CONDITIONS WILL RULE THROUGH THEN WITH ONLY A COUPLE
OF PATCHES OF 6K FT CLOUDS AND SOME THIN HIGH CLOUDS OVERHEAD.
THE VFR CONDITIONS WILL CONTINUE OVERNIGHT. WE ARE MONITORING THE
TRENDS FOR A FEW SHOWERS AND/OR STORMS TO SINK SOUTH INTO THE I-96
TERMINALS EXTREMELY LATE TONIGHT AND ON MON. A FAIR AMOUNT OF UNCERTAINTY
REGARDING THIS POTENTIAL PCPN EXISTS AS IT SHOULD BE WANING AS IT
APPROACHES. WE BELIEVE IT IS TOO LOW AT THIS POINT IN TIME TO HAVE
IN THE FCST PRIOR TO 18Z. WIND GUSTS WILL COME UP ON MON AND
CLOUDS WILL BECOME A LITTLE MORE WIDESPREAD. VFR CONDITIONS SHOULD
CONTINUE TO RULE UNLESS THE PCPN MAKES IT IN EARLIER.
&&
.MARINE...
ISSUED AT 350 PM EDT SUN AUG 25 2013
WITH THE WINDS IN THE BOUNDARY LAYER FORECAST TO BE 20 - 35 KNOTS
INTO MONDAY EVENING IT SEEMS MORE THAN REASONABLE TO KEEP THE
BEACH HAZARD STATEMENT GOING AND THE SMALL CRAFT ADVISORY.
&&
.HYDROLOGY...
ISSUED AT 350 PM EDT SUN AUG 25 2013
WHILE LARGE AREA HEAVY RAINFALL IS NOT EXPECTED... THERE IS LITTLE
QUESTION WITH ALL THE PRECIPITABLE WATER OVERHEAD THE NEXT 2-3
DAYS... IF WE DO SEE ANY THUNDERSTORMS SOME VERY HEAVY RAINFALL
SHOULD BE EXPECTED AS WELL AS LOCALIZED FLOODING IF THE STORMS
MOVE OVER AN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE MONDAY NIGHT FOR MIZ037-043-
050-056.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR LMZ846>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 PM CDT SUN AUG 25 2013
.SYNOPSIS...
ISSUED AT 359 PM CDT SUN AUG 25 2013
NOT MUCH HAS CHANGED IN THE UPPER LEVELS IN THE LAST 24 HRS...WITH A
598 DM HIGH CENTERED OVER MISSOURI THAT IS STILL FLANKED BY TROUGHS
ON EITHER COAST OF NOAM. ACROSS THE ROCKIES...WATER VAPOR IMAGERY IS
SHOWING A TROPICAL MOISTURE PLUME FROM THE REMNANTS OF AN ERN
PACIFIC TROPICAL SYSTEM CURRENTLY OVER THE BAJA PENINSULA THAT IS
NOW WORKING ITS WAY AROUND THE WRN PERIPHERY OF THE MISSOURI HIGHS
AND ALREADY MOVING UP INTO WYOMING...LIKELY REACHING THE UPPER MS
VALLEY MONDAY.
AT THE SFC A TROUGH OF LOW PRESSURE WAS SITUATED FROM CENTRAL SODAK
NE TO NEAR INL. STRONG PRESSURE GRADIENT IS STILL IN PLACE...WITH
BREEZY SOUTHWEST WINDS CONTINUING. WITH TEMPS IN THE LOW TO MID 90S
AND DEWPS IN THE LOW TO MID 70S...STARTING TO SEE HEAT INDICES CLIMB
TO OVER 100 DEGREES...WITH VALUES OF MLCAPE UP SAFELY IN THE HEALTHY
RANGE BETWEEN 3500 AND 6000 J/KG.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
AS CAN BE IMAGINED...WITH A CAPPED...WEAKLY FORCED...HIGH CAPE
ENVIRONMENT...CONFIDENCE IS STILL QUITE LOW ON WHERE/IF CONVECTION
WILL FIRE LATER THIS EVENING. ONE THING IS FOR SURE...PRESENCE OF
ENOUGH INSTABILITY IS NOT AN ISSUE!
WHEN LOOKING AT THE SPC MESO ANALYSIS AND SATELLITE ALONG
WITH A FEW INSTABILITY/MOISTURE TRANSPORT FIELDS FROM THE
DETERMINISTIC MODELS YOU CAN GET A SENSE OF HOW THINGS SHOULD TRY TO
UNFOLD THIS EVENING. FROM THE MESO ANALYSIS SIDE OF THINGS...THERE
IS A GRADIENT IN THE MLCAPE FIELD ACROSS CENTRAL MN...WHICH IS
COINCIDENT WITH THE NRN EDGE OF THE STEEPER MID LEVEL LAPSE RATES
ASSOCIATED WITH AN EML AND STRONGER CAPPING. JUST NORTH OF THE
MLCAPE GRADIENT...THE 20Z ANALYSIS SHOWS H7 DEWPOINTS BETTER THAN
10C ACROSS THE SRN END OF THE DLH/FGF FORECAST AREAS. WITHIN THIS
ZONE OF HIGHER MOISTURE AT H7 MOISTURE...A SHALLOW CU FIELD HAS
DEVELOPED BENEATH A FEW BITS OF ACCUS THAT STRETCH FROM AROUND
FERGUS FALLS OVER TOWARD DULUTH. BEST GUESS RIGHT NOW IS THAT IF
STORMS ARE TO DEVELOP...IT WILL BE WITHIN THIS ZONE...LIKELY CLOSER
TO 00Z.
IN ADDITION...MODELS SHOW THE LLJ AND ASSOCIATED MOISTURE ADVECTION
VEERING SOME AND SAGGING SOUTH THROUGH THE NIGHT. THE AREA OF CLOUDS
REFERENCED ABOVE ALSO SITS ON THE NRN EDGE OF THE MAIN MOISTURE
TRANSPORT PLUME AT H85...WHICH MOST GUIDANCE SHOW COMING DOWN TO
ABOUT I-94 OVERNIGHT. IF SOMETHING CAN GET GOING...THE PRESENCE OF
THE LLJ SHOULD KEEP THE ACTIVITY GOING THROUGH MUCH OF THE NIGHT.
WITH THE RAP AND MOST OTHER MODELS SHOWING THE STRONGEST MOISTURE
TRANSPORT IN THE H85-H7 LAYER RESIDING OVER ERN MN/WRN
WI...CONTINUED TO ADVERTISE LIKELY POPS IN ERN AREAS...THAT TAIL OFF
TO LOW CHANCE POPS IN THE WEST FOR TONIGHT.
FROM THE SEVERE END OF THINGS...AN ENVIRONMENT ASSOCIATED WITH HIGH
MOISTURE CONTENT /PWATS CURRENT NEAR 2 INCHES/...DEEP MELTING
LAYERS...AND WEAK SHEAR MEANS LARGE HAIL WILL BE TOUGH TO COME BY.
HOWEVER...VALUES OF DCAPE UP AROUND 1500 J/KG INDICATES THE WIND
POTENTIAL IS CERTAINLY STILL THERE IF WE CAN GET ANY DEEP MOIST
CONVECTION GOING.
WHAT HAPPENS TONIGHT WILL GO A LONG WAY IN DETERMINING WHERE ANY
POTENTIAL CONVECTION CAN FIRE UP MONDAY AFTERNOON. THE QUESTION FOR
TOMORROW IS FAR SOUTH CAN THE BOUNDARY SLOWLY HEADING FOR CENTRAL MN
MAKE IT TONIGHT. IF WE DO SEE A GOOD AMOUNT OF CONVECTION
OVERNIGHT...THEN THERE IS A GOOD CHANCE THAT THE BOUNDARY CAN MAKE
IT DOWN TO ABOUT I-94. IF WE DO NOT SEE MUCH CONVECTION
TONIGHT...THEN IN ALL LIKELIHOOD...THE BOUNDARY WILL REMAIN NORTH OF
THE MPX AREA...WITH ANOTHER DAY OF CAPED SUNNY SKIES ENSUING. THE
NAM/SREF WOULD SUPPORT THE SRN IDEA...WHILE THE GFS/ECMWF/GEM GO
NORTH. FOR NOW WENT WITH CHANCE POPS AFTER 21Z FOR AREAS NORTH OF
I-94. FROM THE SEVERE PERSPECTIVE...ABOUT THE ONLY THING DIFFERENT
ABOUT MONDAY COMPARED TO TODAY IS THAT THE BELT OF STRONGER
WESTERLIES WILL HAVE SAGGED SOUTH A BIT MORE...INCREASING THE AMOUNT
OF DEEP LAYER SHEAR...WHICH WILL MAKE THE RISK OF LARGE HAIL A BIT
HIGHER OWING TO THE CHANCE OF GETTING AT LEAST WEAK SUPERCELL
STRUCTURES GOING.
LAST STOP IS WITH TEMPERATURES. OVERNIGHT...EXPECT CENTRAL MN TO
COOL A FEW DEGREES MORE THAN THEY DID LAST NIGHT AS THE PRESSURE
GRADIENT WEAKENS...ALLOWING FOR SOME RADIATIONAL COOLING TONIGHT.
STILL...WITH DEWPS AROUND 70...MOST PLACES SHOULD STILL STAY ABOVE
THAT MARK. FOR THE TWIN CITIES AND PLACES FARTHER SOUTH/EAST...WINDS
WILL REMAIN IN PLACE /THOUGH NOT AS STRONG AS LAST NIGHT/...WHICH
WILL KEEP SOME FORM OF MIXING GOING AND ONCE AGAIN MAKE IT A
STRUGGLE FOR A LOT OF PLACES TO DROP BELOW 80 WITHOUT THE HELP OF
RAIN.
FOR HIGHS TOMORROW...925-850 MB TEMPS ACTUALLY INCREASE A DEGREE OR
TWO AS COMPARED TO TODAY...WHICH WOULD THEORETICALLY MEAN WE COULD
GET A DEGREE OR TWO WARMER. HOWEVER...THERE IS THE POTENTIAL FOR A
BIG BUST WITH HIGHS TOMORROW DEPENDING ON WHAT HAPPENS WITH STORMS
TONIGHT. IF WE DO END UP SEEING FAIRLY WIDESPREAD AND ROBUST
CONVECTION OVERNIGHT...THIS WOULD LIKELY LEAVE BEHIND PLENTY OF
DEBRIS COLD COVER...PUTTING A DAMPER ON TEMPERATURES. THE HIRES NMM
EAST DOES EXACTLY THAT WITH CONVECTION OVERNIGHT. THE RESULTING
CLOUD COVER IT GENERATED FOR THE NEXT DAY RESULTED IN IT ONLY
GENERATING HIGHS IN THE MID/UPPER 80S. AT THE OTHER END OF THE
SCALE...A NIGHT OF LITTLE CONVECTION WILL RESULT IN ANOTHER DAY OF
LOTS OF SUN. IN THAT CASE...THEN HIGHS TOMORROW WOULD BE A DEGREE OR
TWO WARMER THAN TODAY...WITH HIGHS IN THE MID/UPPER 90S AND A FEW
100 DEGREE READINGS NOT OUT OF THE QUESTION IN WRN MN. AT ANY
RATE...DID NOT SEE ANYTHING GLARING CHANGE WITH THE TEMP FORECAST
TODAY THAT REQUIRED ANY CHANGES IN THE GOING HEAT HEADLINES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
LONG TERM TRENDS CONTINUE TO SHOW HOT AND HUMID CONDITIONS WILL
CONTINUE THROUGH AT LEAST TUESDAY. LOCATION OF FRONTAL BOUNDARY
MONDAY NIGHT WILL DETERMINE TO WHAT EXTENT/LOCATION CONVECTIVE ACTIVITY
WILL DEVELOP OVER THE CWA. VARIOUS DETERMINISTIC MODELS SHOW THIS
BOUNDARY LIFTING SLOWLY BACK NORTH MONDAY NIGHT AND INTO TUESDAY
AS WEAK COOL FRONT/SURFACE LOW MOVES THROUGH THE AREA. WILL
CONTINUE THE CHANCE POPS OVER THE NORTHEAST THIRD OF THE AREA FOR
TUESDAY...WHICH SHOULD EXIT THE CWA BY TUESDAY EVENING. EXPECT
TEMPERATURES TO RANGE IN THE MID/SOME UPPER 90S AND DEWPOINTS
POOLING AHEAD OF BOUNDARY INTO THE LOWER 70S. HEAT INDEX VALUES
WILL RANGE 100F TO 105F WITH THE CURRENT HEAT ADVISORY/WARNING
STILL LOOKING GOOD CONTINUING THROUGH TUESDAY.
SOME COOLING BEHIND THE FRONT LINGERING INTO FRIDAY...MAINLY OVER
THE EASTERN PORTION OF THE CWA. RIDGING ALOFT DEVELOPS THEREAFTER
WITH SURFACE FRONT MEANDERING OVER CENTRAL MINNESOTA AGAIN INTO
THE WEEKEND. THE 12Z ECMWF IS SLOWER BUILDING THE UPPER RIDGE TO
THE EAST...WITH THE MAIN SURGE COMING NEXT SUNDAY. THE GFS BUILDS
IN NORTH BY SATURDAY. WILL GO ALONG WITH PRESENT TREND OF BRINGING
THE 90S BACK INTO THE AREA FOR SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1249 PM CDT SUN AUG 25 2013
BIGGEST SOURCE OF UNCERTAINTY REMAINS WITH IF/WHERE CONVECTION
WILL BE THIS EVENING/OVERNIGHT. LOOKING AT WHERE THE WEAK SFC
TROUGH MENTIONED IN THE UPDATE IS EXPECTED TO BE...ALONG WITH
FORECAST LLJ PLACEMENT...PROBABILITY FOR SEEING CONVECTION TONIGHT
WILL BE BEST ALONG/NORTH OF 94. CONFIDENCE IN STORMS TONIGHT STILL
LOW ENOUGH THAT HELD ANY TS MENTION TO A VC OR PROB30. WITH THAT
TROUGH SETTLING INTO CENTRAL MN OVERNIGHT...WINDS THERE WILL CALM
DOWN CONSIDERABLY...AND WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S
HZ/BR WILL LIKELY BECOME AN ISSUE TOWARD SUNRISE THERE.
KMSP...12Z TAF STILL LOOKED GOOD FOR TIMING OF ANY CONVECTION THIS
EVENING. CONFIDENCE HAS NOT INCREASED ENOUGH TO GO WITH ANYTHING
MORE THAN THE PROB30 AT THIS POINT. IF WE DO NOT SEE ANY
CONVECTION OVERNIGHT...THEN THE HIGH MOISTURE CONTENT AT LOWER
LEVELS WILL LIKELY LEAD TO SOME MINOR ISSUES WITH HAZE MONDAY
MORNING. ANY CONVECTION POSSIBILITIES MONDAY AFTERNOON WILL DEPEND
HEAVILY ON HOW FAR SOUTH ANY CONVECTION TONIGHT CAN PUSH THE
BOUNDARY HEADING FOR CENTRAL MN. THIS FAR OUT...HAVE LEFT ANY
ADDITIONAL TS MENTION OUT...BUT WILL BE SOMETHING TO KEEP AN EYE
ON.
/OUTLOOK FOR KMSP/
TUE...VFR. WIND SW 5-10 KT...BECOMING W/NW IN AFTERNOON.
WED...VFR. WIND NE 5 KT.
THU...VFR. ISOLD SHRA/TS POSSIBLE. WINDS SE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ054>070-073>078-082>085-091>093.
HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ041>045-
047>053.
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ014>016-
023>028.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1242 PM CDT SUN AUG 25 2013
.UPDATE...
HAVE JUST SENT OUT AN UPDATE TO ACCOUNT FOR RECENT AND EXPECTED
CONVECTIVE TRENDS. INSTABILITY IS BUILDING ACROSS THE REGION TODAY
WITH MARGINAL SHEAR OF 30 TO 40 KTS. WE ALSO HAVE A FAIRLY DECENT
CAP...WITH 700MB TEMPS OF 10C PLUS OVER MOST OF THE FORECAST AREA.
WE ARE GOING TO NEED A DECENT TRIGGER TO GET PAST ALL THAT.
SURFACE FEATURES AT THIS TIME ARE A LITTLE TOO WEAK...BUT THERE IS
A WEAK SHORTWAVE ON VISIBLE SATELLITE IMAGERY OVER NORTHERN SOUTH
DAKOTA...ASSOCIATED WITH A WEAK ENHANCEMENT ON WV SATELLITE
IMAGERY THAT MAY PROVIDE JUST ENOUGH LIFT TO GENERATE STORMS. IT
SHOULD BE MOVING INTO THE SOUTHWESTERN PORTIONS OF THE FORECAST
AREA AROUND 01Z THIS EVENING. IT WILL BE MOVING OVER THE VERY
UNSTABLE AIRMASS OVER EASTERN SOUTH DAKOTA HERE IN THE NEXT FEW
HOURS...SO IF IT IS GOING TO BE ABLE TO GENERATE CONVECTION WE
SHOULD KNOW SOON.
&&
.PREV DISCUSSION... /ISSUED 729 AM CDT SUN AUG 25 2013/
AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. IT WILL BE HUMID WITH DEWPOINTS IN THE
UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY THE
SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE
WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 69 89 68 87 / 50 40 50 40
INL 61 88 67 86 / 0 40 60 30
BRD 69 94 72 91 / 50 40 50 20
HYR 71 92 71 92 / 60 50 50 30
ASX 69 85 68 86 / 50 40 50 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY UNTIL 9 PM CDT MONDAY FOR MNZ033>038.
WI...HEAT ADVISORY UNTIL 9 PM CDT MONDAY FOR WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...LE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
256 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
UDPATED THE NEAR TEAM TO BRING POPS IN ERLR FROM THE MCS THAT IS
MOVING ACRS ONT AND QUE AND THE NERN GREAT LAKES. THE HRRR HAS
BEEN SHOWING THAT THIS PRECIP WILL GET INTO NC AND EC NY BETWEEN
1Z AND 6Z WITH THE RAP NOW SPEEDING THE ARRIVAL UP TOO OVER THE
OTHER MODELS. SINCE THESE ARE RAPID UPDATE CYCLE MODELS AND THE
RADAR TRENDS ARE CLSR TO THESE MODELS I NOW BRING IN PRECIP MUCH
ERLR IN LINE WITH KBUF/S RECENT UPDATE. OTHERWISE...NO OTHER
CHANGES THRU MONDAY.
PREVIOUS DSCN BELOW...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING ON
THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION IS
TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY
LATEST RADAR LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT
THIS IS A MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL
GUIDC AND SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET.
SO FOR NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR
6Z...BUT WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD
LIKE TO SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE
PRECIP IS REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
I KEPT TUESDAY DRY AS NY AND PA IS IN BETWEEN SYSTEMS WITH A SMALL
BUBBLE HIGH OVERHD. ALL SYNOPTIC MODELS INDICATE THAT THE MAJORITY
OF THE DAY IS DRY WITH JUST A FEW HUNDRENTHS POSSIBLE IN THE SW
AND FAR NE PART OF OUR CWA.
FOR WEDNESDAY...MODELS ARE IN AGREEMENT THAT ANOTHER MCS AND SHRT
WAVE WILL AFFECT THE REGION. MODEL TIMING AND PLACEMENT IS
UNCERTAIN THIS FAR OUT. SO I HAVE GENERIC CHC POPS FOR SHRA AND
TSRA TO COVER IN LINE WITH NEIGHBORING OFFICES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES TO THIS PART OF THE FORECAST. THE BROAD...AND
HOT LATE SEASON RIDGE OVER MUCH OF THE WESTERN AND CNTRL CONUS IS
STILL EXPECTED TO EXPAND INTO THE NORTHEAST BY THE END OF THE
PERIOD WITH REGIONAL HIGH TEMPERATURES EXPECTED TO RISE WELL INTO
THE MID 80S OVER NEXT WEEKEND.
THE ADVERTISED FRONTAL SYSTEM...POSSIBLY ACCOMPANIED BY A COMPLEX
SECONDARY LOW DEVELOPMENT ON THE BOUNDARY...IS STILL FORECAST TO
BE MOVING EAST OF THE AREA IN THE WEDNESDAY NIGHT-THURSDAY TIME
FRAME. THE FORECAST WILL STILL FEATURE DECREASING POPS WITH TIME
INTO THURSDAY...THEN WITH THE BROAD RIDGE IN PLACE THURSDAY NIGHT
AND NEXT WEEKEND LOOKS RAIN FREE AND WARMER AT THIS TIME.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
FOR A GENERALLY VFR SITUATION...THIS FORECAST HAS SOME INTERESTING
WRINKLES BUILT IN. A RATHER STUBBORN THUNDERSTORM COMPLEX MOVING
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON LOOKS TO BE
TARGETING OUR TERMINALS FOR THIS EVENING. THE SYSTEM WILL LOSE A LOT
OF IT`S CONVECTIVE PUNCH AS IT PULLS AWAY FROM THE SOURCE REGION
OF BEST INSTABILITY OVER THE UPPER MIDWEST AND WESTERN ONTARIO...BUT
WILL STILL LIKELY BRING IN SOME MID LVL CIGS AND POSSIBLE SHOWERS.
LINEAR EXTRAPOLATION BRINGS THE LEADING EDGE OF SYSTEM INTO THE
KSYR-KRME-KITH AREAS TOWARD 00Z WITH SHOWER POTENTIAL FOR A FEW
HOURS THEREAFTER. NOT SURE IF MUCH RAIN WILL REACH THE GROUND AS
LAYERS BETWEEN 5K-10K FT ARE PRETTY DRY. COULD TURN OUT TO BE JUST
INSIGNIFICANT -SHRA FROM THE MID DECK.
LATER ON TONIGHT...THE SWLY FLOW ALOFT DOES TEND TO MOISTEN UP THE
LOWER LEVELS OF THE ATMOSPHERE WITH CIGS PROBABLY LOWERING INTO
THE 5 KFT RANGE BY MORNING. THERE STANDS TO BE ANOTHER ROUND OF
SHOWERS DEVELOPING TOWARD MORNING AS MINOR UPPER LEVEL IMPULSES
MOVE THROUGH THE NORTHWESTERLY JET LEVEL FLOW. MVFR SHOULD BE
LIMITED TO MAYBE SOME LIGHT FOG AT KELM...ALTHOUGH THERE IS SOME
CHANCE FOR LOWER CIGS IN ANY RAIN SHOWERS, BUT THE CONFIDENCE FOR
INCLUDING THAT IN THE FORECAST IS PRETTY LOW.
WINDS GENERALLY LIGHT SOUTHWEST...OR VARIABLE DRAINAGE FLOW IS
EXPECTED THROUGH TONIGHT...THEN INCREASING SW-W UP TO 10 KTS ON
MONDAY.
OUTLOOK...
MON...VFR. OCNL SHRA. CHC TSRA IN PM.
TUE...VFR. CHC SHRA/TSRA PM. LOCAL MVFR.
WED...VFR. SHRA/TSRA LIKELY. CHC MVFR.
THU...VFR.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
226 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING
ON THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION
IS TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY LATEST RADAR
LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT THIS IS A
MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL GUIDC AND
SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET. SO FOR
NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR 6Z...BUT
WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD LIKE TO
SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE PRECIP IS
REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LINGERING SHRA/TSRA PSBL MON EVNG AS FNTL SYSTEM DEPARTS AND WEAK
HI PRES BUILDS INTO THE RGN. NAM/GFS PROFILES BOTH SHOW FAIRLY SIG
LOW LVL MSTR BEHIND THIS BNDRY PERSISTING INTO TUE MRNG...WHICH
SHUD BURN OFF BY LATE MRNG LEAVING PS SKIES.
THE NXT S/WV AND FNTL SYSTEM APRCHS TUE NGT. ALL MDLS SUGGEST MCS
POTNL BUT THERE ARE SIG DIFFS W/RESPECT TO THE TRACK OF THE SFC
LOW/MCS. GFS/NAM SUGGEST A MORE SWD TRACK OF THE LOW AND
MCS...WHILE THE EURO/GEM INDICATE A MORE NRLY TRACK. NO DOUBT
LATER FCSTS WILL BE TWEAKED AS WE GET CLOSER TO THE EVENT...SO FOR
NOW WENT WITH MOS POPS (CHC) FOR THESE TIME PDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES TO THIS PART OF THE FORECAST. THE BROAD...AND
HOT LATE SEASON RIDGE OVER MUCH OF THE WESTERN AND CNTRL CONUS IS
STILL EXPECTED TO EXPAND INTO THE NORTHEAST BY THE END OF THE
PERIOD WITH REGIONAL HIGH TEMPERATURES EXPECTED TO RISE WELL INTO
THE MID 80S OVER NEXT WEEKEND.
THE ADVERTISED FRONTAL SYSTEM...POSSIBLY ACCOMPANIED BY A COMPLEX
SECONDARY LOW DEVELOPMENT ON THE BOUNDARY...IS STILL FORECAST TO
BE MOVING EAST OF THE AREA IN THE WEDNESDAY NIGHT-THURSDAY TIME
FRAME. THE FORECAST WILL STILL FEATURE DECREASING POPS WITH TIME
INTO THURSDAY...THEN WITH THE BROAD RIDGE IN PLACE THURSDAY NIGHT
AND NEXT WEEKEND LOOKS RAIN FREE AND WARMER AT THIS TIME.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
FOR A GENERALLY VFR SITUATION...THIS FORECAST HAS SOME INTERESTING
WRINKLES BUILT IN. A RATHER STUBBORN THUNDERSTORM COMPLEX MOVING
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON LOOKS TO BE
TARGETING OUR TERMINALS FOR THIS EVENING. THE SYSTEM WILL LOSE A LOT
OF IT`S CONVECTIVE PUNCH AS IT PULLS AWAY FROM THE SOURCE REGION
OF BEST INSTABILITY OVER THE UPPER MIDWEST AND WESTERN ONTARIO...BUT
WILL STILL LIKELY BRING IN SOME MID LVL CIGS AND POSSIBLE SHOWERS.
LINEAR EXTRAPOLATION BRINGS THE LEADING EDGE OF SYSTEM INTO THE
KSYR-KRME-KITH AREAS TOWARD 00Z WITH SHOWER POTENTIAL FOR A FEW
HOURS THEREAFTER. NOT SURE IF MUCH RAIN WILL REACH THE GROUND AS
LAYERS BETWEEN 5K-10K FT ARE PRETTY DRY. COULD TURN OUT TO BE JUST
INSIGNIFICANT -SHRA FROM THE MID DECK.
LATER ON TONIGHT...THE SWLY FLOW ALOFT DOES TEND TO MOISTEN UP THE
LOWER LEVELS OF THE ATMOSPHERE WITH CIGS PROBABLY LOWERING INTO
THE 5 KFT RANGE BY MORNING. THERE STANDS TO BE ANOTHER ROUND OF
SHOWERS DEVELOPING TOWARD MORNING AS MINOR UPPER LEVEL IMPULSES
MOVE THROUGH THE NORTHWESTERLY JET LEVEL FLOW. MVFR SHOULD BE
LIMITED TO MAYBE SOME LIGHT FOG AT KELM...ALTHOUGH THERE IS SOME
CHANCE FOR LOWER CIGS IN ANY RAIN SHOWERS, BUT THE CONFIDENCE FOR
INCLUDING THAT IN THE FORECAST IS PRETTY LOW.
WINDS GENERALLY LIGHT SOUTHWEST...OR VARIABLE DRAINAGE FLOW IS
EXPECTED THROUGH TONIGHT...THEN INCREASING SW-W UP TO 10 KTS ON
MONDAY.
OUTLOOK...
MON...VFR. OCNL SHRA. CHC TSRA IN PM.
TUE...VFR. CHC SHRA/TSRA PM. LOCAL MVFR.
WED...VFR. SHRA/TSRA LIKELY. CHC MVFR.
THU...VFR.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
138 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING A SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING
ON THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION
IS TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY LATEST RADAR
LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT THIS IS A
MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL GUIDC AND
SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET. SO FOR
NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR 6Z...BUT
WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD LIKE TO
SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE PRECIP IS
REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LINGERING SHRA/TSRA PSBL MON EVNG AS FNTL SYSTEM DEPARTS AND WEAK
HI PRES BUILDS INTO THE RGN. NAM/GFS PROFILES BOTH SHOW FAIRLY SIG
LOW LVL MSTR BEHIND THIS BNDRY PERSISTING INTO TUE MRNG...WHICH
SHUD BURN OFF BY LATE MRNG LEAVING PS SKIES.
THE NXT S/WV AND FNTL SYSTEM APRCHS TUE NGT. ALL MDLS SUGGEST MCS
POTNL BUT THERE ARE SIG DIFFS W/RESPECT TO THE TRACK OF THE SFC
LOW/MCS. GFS/NAM SUGGEST A MORE SWD TRACK OF THE LOW AND
MCS...WHILE THE EURO/GEM INDICATE A MORE NRLY TRACK. NO DOUBT
LATER FCSTS WILL BE TWEAKED AS WE GET CLOSER TO THE EVENT...SO FOR
NOW WENT WITH MOS POPS (CHC) FOR THESE TIME PDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
4 AM SUN UPDATE... NOT MUCH CHG TO THE PREV FCST...AS EC/GFS/WPC
CONSENSUS STILL SHOWS AN EXPANSIVE SUBTROP UPR RIDGE TO BE THE
MAIN WX INFLUENCE OVER MUCH OF THE CONUS THIS PD. ALTHOUGH THIS
RIDGE IS INITIALLY CENTERED OVER THE MIDDLE OF THE COUNTRY AT MID-
WEEK (START OF THE PD)...IT IS PROGGED TO SLOWLY EXPAND EWD WITH
TIME BY NEXT WEEKEND. AS A RESULT...SEASONABLE TEMPS WED-FRI
(HIGHS FROM THE MID 70S-LWR 80S) SHOULD WARM MORE SOLIDLY INTO THE
80S THEREAFTER.
AS FOR THE DAILY SENSIBLE WX...A COLD FRNTL BNDRY IS STILL
EXPECTED TO CROSS NY/PA FROM NW TO SE SOMETIME LTR WED OR EARLY
THU...WITH SHWRS/TSTMS ALG AND AHD OF THIS FEATURE. AS THIS SYSTEM
IS STILL SVRL DAYS AWAY...WE`LL CONTINUE TO ADVERTISE CHC POPS FOR
NOW ON WED AND WED NGT...DECREASING WITH TIME BY THU. FROM FRI
THROUGH NEXT WEEKEND...RAIN-FREE CONDS LOOK PROBABLE...WITH
RIDGING BUILDING IN BOTH SFC AND ALOFT.
PREV DISC... ECMWF AND GFS IN PRETTY GOOD AGREEMENT REGARDING A
STRONG RIDGE BUILDING THROUGHOUT THE CENTRAL U.S. AND EVENTUALLY
SPREADING ITS INFLUENCE EASTWARD.
A TROF WILL EXTEND ACROSS THE GREAT LAKES TUESDAY NIGHT, WITH AN
ASSOCIATED SFC CYCLONE AND COLD FRONT PROGGED TO PULL THROUGH
NY/PA ON WEDNESDAY. CHANCE TO SCATTERED THUNDERSTORM COVERAGE IS
FORECAST THROUGH WEDNESDAY.
A DRY NORTHWEST FLOW WILL DEVELOP FOR THURSDAY AND FRIDAY, AS THE
PLAINS RIDGE BUILDS THROUGH OHIO AND MICHIGAN. FAIR WEATHER AND
MAINLY CLEAR SKIES ARE FORECAST FOR NY/PA.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
12Z SUN UPDATE... ONGOING FOG AT KELM SHOULD BURN OFF BY ARND 14Z.
OTHWS...VFR WILL CONTINUE TO PREVAIL.
WE MAY SEE A FEW SHWRS IN THE VICINITY OF KRME/KSYR TWDS 10-12Z
MON...BUT PROBABILITIES DON`T SEEM HIGH ENUF TO MAKE MENTION OF
THIS IN THE TERMINALS ATTM.
OUTLOOK...
MON THROUGH WED...ALTHOUGH VFR CONDS ARE PROBABLE THE MAJORITY OF
THE TIME...PERIODIC SHWRS/TSTMS ARE PSBL (MOST LIKELY DURG THE
AFTN/EVE HRS). ANY SUCH SHWR/TSTM COULD BRIEFLY PRODUCE
RESTRICTIVE CONDS.
BY THU...GENERALLY VFR CONDS ARE EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DJP/MLJ
AVIATION...KAH/MLJ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
521 PM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 520 PM CDT SUN AUG 25 2013
QUICK UPDATE TO INCREASE AND EXPAND POPS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA FOR THE REMAINDER OF THE EVENING AND
OVERNIGHT. SURFACE BASED CONVECTION HAS BEEN INCREASING ACROSS
SOUTHWEST NORTH DAKOTA AND NORTHWEST SOUTH DAKOTA SINCE 2130 UTC
GIVEN THE LOSS OF CAPPING AND INCREASING UPPER LEVEL FORCING WITH
THE SHORTWAVE ENTERING WESTERN NORTH DAKOTA EVIDENT ON THE LATEST
WATER VAPOR IMAGERY. DEEP LAYER SHEAR ON THE ORDER OF 30-35 KTS
SUPPORTS THE POTENTIAL FOR PERHAPS A SUPERCELL OR TWO...WITH ML
CAPE VALUES AROUND 1500 J/KG. WHILE HIGH FREEZING LEVELS LIMIT THE
HAIL THREAT...DOWNDRAFT CAPE VALUES NEAR 1400 J/KG SUGGEST A
DAMAGING WIND THREAT WITH THE STRONGER STORMS. THE 18 UTC NAM AND
20 UTC HRRR ARE HANDLING THE CONVECTION WELL...WITH THE HRRR
SUGGESTING THE CONVECTION WILL PROPAGATE INTO BISMARCK AND MANDAN
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
LATE SUNDAY AFTERNOON...SURFACE HIGH PRESSURE WAS ACROSS SOUTHERN
MANITOBA. A WEAK COLD FRONT WAS SLIDING SOUTH ACROSS CENTRAL NORTH
DAKOTA. ON SATELLITE...WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
MOVE THROUGH WYOMING INTO CENTRAL MONTANA. THIS FEATURE IS
SUPPORTING CONVECTION ACROSS EASTERN MONTANA. SOME SHOWERS AND
ISOLATED THUNDERSTORMS SHOULD ENTER WEST CENTRAL AND NORTHWEST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. THEN PROGRESSIVELY TRACKED
THE SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS INTO WESTERN NORTH
DAKOTA OVERNIGHT AND INTO CENTRAL NORTH DAKOTA MONDAY. WITH THE
BASIC RIDGE PATTERN IN PLACE OVER THE CENTRAL AND NORTHERN
PLAINS...CONTINUED WARM TEMPERATURES EXPECTED ON MONDAY...HOWEVER
WITH COLD FRONT BRINGING A SLIGHT RELIEF WITH HIGHS IN THE UPPER 80S
NORTH TO LOWER 90S SOUTH ON MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE LONG
TERM FORECAST PERIOD...WHICH WILL CONTINUE TO INDICATE ABOVE AVERAGE
DAYTIME HIGH TEMPERATURES. SOUTHERN PORTIONS OF THE CWA COULD FLIRT
WITH HEAT ADVISORY CRITERIA LATER IN THE WEEK. IN ADDITION...ALMOST
DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES EVERY DAY
BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY AND INTO MONDAY NIGHT THE
ECMWF/GEM APPEAR STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND
BRING QPF ACROSS THE NORTH. THE SOUTH MAY REMAIN CAPPED UNDER WARM
MID LEVEL TEMPERATURES.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
SATURDAY BUT TIMING AND PLACEMENT DIFFERENCES CONTINUE BETWEEN
MODELS AND MODEL RUNS. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED
SOLUTION FOR PRECIPITATION. THIS WILL MEAN BETTER CHANCES WEDNESDAY
THROUGH THURSDAY AFTERNOON...THEN CHANCES ARE ON AND OFF FRIDAY
NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 310 PM CDT SUN AUG 25 2013
AT 3 PM CDT...A COLD FRONT EXTENDED ACROSS CENTRAL NORTH DAKOTA. THE
FRONT IS FORECAST TO SLIDE SOUTH TONIGHT. A SHORTWAVE TROUGH IS
IDENTIFIED ON SATELLITE MOVING INTO EASTERN MONTANA. WIDELY
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE INTO WESTERN
NORTH DAKOTA IMPACTING KISN/KDIK THIS EVENING. HOWEVER...TOO WIDELY
SCATTERED TO MENTION TSRA AT THIS TIME. AS THE SHORTWAVE MOVES
THROUGH WESTERN NORTH DAKOTA TONIGHT AND MONDAY WILL SEE PROGRESSIVE
EASTWARD CHANCE OF THUNDERSTORMS. AGAIN...TO UNCERTAIN AT THIS
TIME...BUT WILL USE VCTS TO INDICATE GENERAL SENSE OF THUNDERSTORMS.
VFR EXPECTED AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1209 PM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 1155 AM CDT SUN AUG 25 2013
AT NOON CDT...A WEAK FRONTAL BOUNDARY ACROSS NORTHERN NORTH DAKOTA
IS FORECAST TO SLIDE SLOWLY SOUTH. LITTLE WEATHER WITH THIS
FEATURE AS IT LIES BENEATH AN H500 RIDGE. WATER VAPOR IMAGERY IS
TRACKING A SHORTWAVE MOVING NORTHEAST UP THE WESTERN PORTION OF
THE RIDGE WHICH SHOULD SUPPORT SOME CONVECTION ACROSS WESTERN NORTH
DAKOTA LATER TONIGHT. FOR THIS UPDATE...REMOVED THE SLIGHT CHANCE
FOR THUNDERSTORMS SOUTHEAST. WILL LEAVE TEMPS/WINDS AS IS.
UPDATE ISSUED AT 1000 AM CDT SUN AUG 25 2013
WEAK HIGH PRESSURE PATTERN OVER THE STATE THIS MORNING WITH A WEAK
TROUGH OF LOW PRESSURE LINGERING ACROSS SOUTH CENTRAL AND
SOUTHEAST NORTH DAKOTA. THIS COULD BE THE FOCUS FOR AN ISOLATED
THUNDERSTORM THIS MORNING. WILL RE EVALUATE THE POTENTIAL FOR THE
AFTERNOON...FOR NOW LEFT A SLIGHT CHANCE THUNDERSTORMS SOUTHEAST
THIS MORNING WHERE HRRR MODEL GENERATES ISOLATED CONVECTION. ARE
OF CLOUDS IN CENTRAL/EASTERN MONTANA APPEAR TO BE ASSOCIATED WITH
A SHORT WAVE CENTERED IN WESTERN WYOMING MOVING NORTHEAST. THE
RIDGE MAY PREVENT THE CLOUDS AND SHOWERS/THUNDERSTORMS FROM MAKING
MUCH EASTWARD ADVANCEMENT INTO WESTERN NORTH DAKOTA THIS
AFTERNOON... ALTHOUGH NEW NAM GENERATES SOME THUNDERSTORMS AFTER 3
PM. DON`T HAVE ENOUGH CONFIDENCE TO MOVE UP THE TIME TABLE FORM
THIS EVENING INTO THE IS AFTERNOON.
UPDATE ISSUED AT 644 AM CDT SUN AUG 25 2013
MAINLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS
MORNING. HIGH PRESSURE OVER THE WEST WITH DRIER AIR WORKING INTO
THE AREA ALLOWED TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
50S. MEANWHILE A LOW PRESSURE TROUGH REMAINS FROM CENTRAL SOUTH
DAKOTA INTO EAST CENTRAL NORTH DAKOTA WITH MUCH HIGHER HUMIDITIES.
TEMPERATURES HERE HAVE ONLY FALLEN INTO THE UPPER 60S AND LOWER
70S. NO SIGNIFICANT CHANGES TO THE FORECAST THIS UPDATE. DID KEEP
A SLIGHT CHANCE OF THUNDER OVER THE SOUTHEAST NEAR THE WEAK
SURFACE TROUGH. LATEST 06 UTC NAM IS INDICATING LIGHT QPF ENTERING
INTO THE WEST LATER THIS AFTERNOON. WILL LEAVE THIS OUT OF THE
FORECAST FOR NOW BUT WILL LET THE DAY SHIFT MONITOR.
&&
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 303 AM CDT SUN AUG 25
2013
MAIN HIGHLIGHT IN THE SHORT TERM WILL BE ANOTHER HOT DAY WITH
HIGHS WELL INTO THE 90S...HOWEVER THUNDERSTORMS WILL BE CONFINED
TO FAR SOUTH CENTRAL NORTH DAKOTA AND THE SOUTHERN JAMES RIVER
VALLEY.
EARLY THIS MORNING...THE LATEST LOCAL RADAR SHOWS A LINE OF
SHOWERS AND THUNDERSTORMS INITIATING ALONG A FRONTAL BOUNDARY/LOW
CONVERGENCE ZONE...STRETCHING FROM CORSON COUNTY IN SOUTH DAKOTA
NORTHEAST BETWEEN BURLEIGH AND EMMONS COUNTY AND INTO STUTSMAN
COUNTY. WATER VAPOR INDICATIVE OF A SHORTWAVE MOVING THROUGH
CENTRAL NORTH DAKOTA EARLY THIS MORNING PROVIDING THE LIFT NEEDED
TO SUSTAIN AND REDEVELOP THE PRECIPITATION. A COUPLE OF THE
THUNDERSTORMS HAVE COME CLOSE TO SEVERE CRITERIA...AND WILL
CONTINUE TO MONITOR.
FOR TODAY...UPPER LEVEL RIDGING CENTERED OVER CENTRAL KANSAS
COMBINED WITH AN UPPER TROUGH ALONG THE WEST COAST...WILL MAINTAIN
A SOUTHWEST FLOW INTO NORTH DAKOTA. A COUPLE OF SHORTWAVES ARE
FORECAST TO SLIDE ACROSS THE NORTHERN BORDER WITH LITTLE OR NO
AFFECT IN TERMS OF PRECIPITATION. THE AFOREMENTIONED FRONTAL
BOUNDARY IS FORECAST TO SHIFT A BIT FURTHER SOUTH TODAY...INTO
NORTHERN SOUTH DAKOTA. HOWEVER A SHORTWAVE MOVING OUT FROM
COLORADO IS FORECAST TO MOVE INTO CENTRAL SOUTH DAKOTA THIS
AFTERNOON. THIS SHOULD LEAD TO ISOLATED THUNDERSTORMS IN OUR
SOUTHEAST ZONES CLOSEST TO THE FRONT. ELSEWHERE EXPECT MOSTLY
SUNNY...DRY..AND HOT CONDITIONS WITH HIGHS 90F TO 98F. HEAT
INDICES ARE FORECAST IN THE MID TO UPPER 90S IN OUR SOUTH CENTRAL
ZONES AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER
OUTLOOK.
FOR SUNDAY NIGHT...LEE SIDE TROUGH DEVELOPS IN SOUTHEAST MONTANA
AS A COUPLE OF SHORTWAVES ARRIVE VIA THE SOUTHWEST FLOW INTO
WESTERN NORTH DAKOTA. HAVE MENTIONED ISOLATED THUNDERSTORMS WEST
SUNDAY NIGHT WITH DRY CONDITIONS CENTRAL. LOWS WILL AGAIN BE IN
THE 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 303 AM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE
WHICH WILL CONTINUE TO INDICATE VERY WARM DAYTIME HIGH TEMPERATURES.
SOUTHERN PORTIONS OF THE CWA COULD FLIRT WITH HEAT ADVISORY
CRITERIA ON MONDAY AND AGAIN LATER IN THE WEEK. IN ADDITION...
ALMOST DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES
EVERY DAY BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY THE ECMWF/GEM APPEAR
STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND BRING QPF ACROSS
THE NORTH. THE SOUTH WILL LIKELY REMAIN CAPPED UNDER WARM MID
LEVEL TEMPERATURES. THE GFS IS STRONGER WITH THE RIDGING OVER THE
AREA AND KEEPS PRECIPITATION MAINLY NORTH OF THE BORDER.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
FRIDAY BUT TIMING AND PLACEMENT DIFFERENCES INCREASE WITH LESS
CONSENSUS BETWEEN THE MODELS EXISTS THAN THE MODEL RUNS FROM 24
HOURS AGO. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED SOLUTION
FOR PRECIPITATION. MODELS DO INDICATE AT LEAST A TEMPORARY
BREAKDOWN OF THE UPPER RIDGE LATE IN THE PERIOD WITH THE ECMWF A
GOOD 18 TO 24 HOURS QUICKER TO BRING PRECIPITATION CHANCES AND
COOLER TEMPERATURES TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1155 AM CDT SUN AUG 25 2013
AT NOON CDT...A REGION OF HIGH PRESSURE ACROSS SOUTHERN CANADA AND
NORTHERN NORTH DAKOTA WILL BRING VFR CONDITIONS TO THE REGION
THROUGH THE 18Z TAF PERIOD. A WEAK FRONTAL BOUNDARY WILL MOVE TO
SOUTHEAST MONTANA AND SOUTHERN NORTH DAKOTA SUNDAY NIGHT. A
SHORTWAVE TROUGH ACROSS WYOMING INTO SOUTHERN MONTANA WILL BE THE
FEATURES THAT FOCUS SCATTERED THUNDERSTORMS ACROSS WESTERN NORTH
DAKOTA LATE TONIGHT INTO MONDAY MORNING WEST. THIS WILL IMPACT
KDIK-KBIS-KMOT-KISN AFTER 06Z. WILL HANDLE WITH VCTS AS THREAT
FAIRLY ISOLATED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS TULSA OK
1211 PM CDT SUN AUG 25 2013
.DISCUSSION...
THE 18Z TAF DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL BENEATH A MID AND UPPER LEVEL RIDGE OF
HIGH PRESSURE. THE ONLY EXCEPTION WILL BE SOME LIGHT MVFR FOG AT
KBVO...KRVS AND THE W/NW AR TAF SITES AROUND 12Z IN THE MORNING.
SHRA/TSRA CHANCES ARE TOO LOW TO MENTION IN THE TAFS.
LACY
&&
.PREV DISCUSSION... /ISSUED 904 AM CDT SUN AUG 25 2013/
DISCUSSION...
ANOTHER HOT AND HUMID DAY IS IN STORE FOR EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS WITH MID/UPPER RIDGING IN CONTROL. 12Z UPPER
AIR DATA INDICATES 500MB HEIGHTS ARE RISING AND SOME 700MB
MOISTURE REMAINS AT LITTLE ROCK...SHREVEPORT AND FORT WORTH. THIS
WOULD SUGGEST THE BEST POTENTIAL FOR ISOLATED AFTERNOON
SHOWERS/STORMS WILL BE OVER THE HIGH TERRAIN OF SOUTHEAST OKLAHOMA
AND/OR WEST CENTRAL ARKANSAS AND DOWN NEAR THE RED RIVER. COVERAGE
OF PRECIP YESTERDAY WAS VERY LOW...AND WITH THE RISING UPPER
HEIGHTS THAT WILL LIKELY NOT CHANGE TODAY. THE LATEST HRRR SHOWS
HINTS OF ISOLATED DEVELOPMENT DOWN IN THAT REGION. WILL ELECT TO
CARRY SILENT 10 POPS THERE...AND WILL MONITOR THE CU FIELD LATER
TODAY TO SEE IF AN INCREASE IS WARRANTED IN SPOTS.
LACY
PREV DISCUSSION... /ISSUED 320 AM CDT SUN AUG 25 2013/
DISCUSSION...
A LARGE UPPER RIDGE WILL REMAIN PARKED OVER THE AREA THROUGH THE
ENTIRE FORECAST PERIOD. THE GFS IS QUICKER THAN THE ECMWF TO BEGIN
TO BREAK DOWN THE RIDGE NEXT WEEKEND INTO THE FIRST WEEK OF
SEPTEMBER WHICH IS A REVERSAL FROM MODEL RUNS A COUPLE DAYS AGO.
IN THE MEANTIME...HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN WILL
PREVAIL. TEMPERATURES WILL SLOWLY INCH UP LATER THIS WEEK...LIKELY
PEAKING ON FRIDAY OR SATURDAY. STAYED CLOSE TO GUIDANCE
TEMPERATURES THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 94 74 94 74 / 0 0 0 0
FSM 94 73 94 73 / 10 0 0 0
MLC 94 73 95 73 / 10 10 10 0
BVO 94 69 94 69 / 0 0 0 0
FYV 91 67 90 67 / 10 0 0 0
BYV 91 69 90 69 / 0 0 0 0
MKO 94 71 93 71 / 0 0 0 0
MIO 91 71 93 71 / 0 0 0 0
F10 94 73 93 73 / 0 0 0 0
HHW 96 72 96 72 / 10 10 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
419 PM EDT SUN AUG 25 2013
.SYNOPSIS...
DRIER HIGH PRESSURE WILL PERSIST THROUGH MIDWEEK BEFORE AN UPPER
LEVEL DISTURBANCE AND AN ASSOCIATED SURFACE COLD FRONT MOVE THROUGH
THE REGION ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
SHOWERS AND THUNDERSTORMS FOR THE WEEK. WEAK HIGH PRESSURE WILL
RETURN IN THE FRONTS WAKE FOR THE START OF NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
4 PM UPDATE...LITTLE CHANGE EXCEPT TO TOUCH UP SKY...TEMPS AND
DEWPTS FROM LATEST OBS. LATEST RAP DOES PRODUCE SOME LIGHT PRECIP
THIS AFTN IN THE SMOKIES BUT SATELLITE TRENDS SUGGEST THE SCATTERED
CLOUD COVER THERE IS TOO SHALLOW FOR PRECIP. WILL HOLD ON TO DRY
FCST.
AS OF 140 PM EDT SUNDAY...THE PATTERN WILL TRANSITION FROM ONE OF
COLD AIR DAMMING...WITH A FAIRLY TIGHT SFC PRESSURE GRADIENT AND
MODERATE LLVL ADVECTION OF DRY AND COOL AIR...TO ONE WITH A BROAD
RIDGE OF HIGH PRESSURE COVERING THE ENTIRE REGION. THIS WILL SHUT
OFF THE COLD ADVECTION...RESULTING IN MODERATING TEMPERATURES AND
NEARLY CALM WINDS TONIGHT AND MONDAY. THE DEWPOINTS SHOULD STILL
REMAIN LOW WITH SUBSIDENCE ACROSS THE SE STATES. THERE WILL BE SOME
UPSLOPE INDUCED STRATO-CU MUCH OF THE NIGHT ALONG THE BLUE RIDGE.
TOMORROW WE SHOULD SEE A WIDESPREAD CU FIELD DEVELOP ACROSS THE
REGION DURING THE LATE MORNING AND AFTERNOON HOURS.
TONIGHT/S FORECAST LOW TEMPERATURE OF 58 DEGREES AT CHARLOTTE...IF
IT VERIFIES...WILL BE THE COOLEST READING SINCE JUNE 15TH. AND WHILE
CHARLOTTE DID SEE A COUPLE READINGS IN THE 50S LAST AUGUST...THEY
HADN/T SEE READINGS IN THE 50S DURING THIS MONTH SINCE 2004 BEFORE
THAT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AT 150 PM EDT SUNDAY...AN UPPER RIDGE WILL BE CENTERED OVER THE
MIDDLE OF THE NATION MONDAY EVENING...WHILE AN UPPER TROUGH AXIS
REMAINS OFF THE EAST COAST. THE UPPER TROUGH AXIS RETROGRESSES
CLOSER TO THE COAST BY WEDNESDAY....SUCH THAT HEIGHTS FALL ALONG HE
EASTERN SEABOARD.
A SHORTWAVE TROUGH WILL DROP INTO THE ATLANTIC TROUGH MONDAY
NIGHT...CROSSING THE NORTHEAST USA. ANOTHER...WEAKER SHORTWAVE WILL
FOLLOW SUIT LATE TUESDAY AND CROSS THE MID ATLANTIC REGION...AND A
THIRD SYSTEM CROSS THE CAROLINAS ON WEDNESDAY.
WEAKENING HIGH PRESSURE WILL BE IN PLACE OVER THE CAROLINAS AND GA
ON MONDAY NIGHT. MODEL TIME HEIGHTS SHOW VERY DRY AIR BETWEEN 850 MB
AND 300 MB...WITH LIMITED LOW LEVEL MOISTURE. ON TUESDAY A SURFACE
TROUGH IS EXPECTED TO FORM IN THE LEE OF THE MOUNTAINS AS THE
SURFACE HIGH MOVES WEST ACROSS THE GULF STATES...WHILE BOTH LOW AND
MID LEVEL MOISTURE INCREASE FROM THE NORTH AHEAD OF A COLD FRONT
APPROACHING THE OH RIVER VALLEY. THE LEE TROUGH PERSISTS INTO
WEDNESDAY...WHILE THE MODELS CONTINUE TO SHOW A RELATIVE DRY
LAYER...ALBEIT SLOWLY MOISTENING...BETWEEN AROUND 600 MB AND 800 MB.
PRECIPITATION IS NOT EXPECTED ON MONDAY NIGHT THROUGH TUESDAY NIGHT
WITH INITIALLY DRY MID LEVELS...AND PRONOUNCED SUBSIDENCE INVERSION.
PRECIPITATION CHANCES INCREASE ON WEDNESDAY WITH INCREASING MOISTURE
AND INSTABILITY...AND COOLING ALOFT...BUT WILL STILL REMAIN IN THE
CHANCE CATEGORY. TEMPERATURES WILL WARM FROM SLIGHTLY BELOW NORMAL
MONDAY NIGHT...TO NEAR NORMAL FROM TUESDAY THROUGH WEDNESDAY...AS
THE AIR MASS MODIFIES...AND HIGH PRESSURE MOVES OFF TO THE
WEST...INTRODUCING A LIGHT WESTERLY DOWNSLOPE FLOW COMPONENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 130 PM EDT SUNDAY...THE MEDIUM RANGE PICKS UP AT 00Z ON
THURSDAY WITH THE LARGE UPPER RIDGE CENTERED OVER THE CENTRAL CONUS
AND NORTHERN STREAM UPPER TROFFING OVER SOUTHEASTERN CANADA. THE
UPPER RIDGE IS EXPECTED TO REMAIN LARGELY IN PLACE IF NOT SLIDE A
BIT WESTWARD OVER THE NEXT FEW DAYS AND THEN FLATTEN OVER THE
WEEKEND. THIS WILL RESULT IN MINOR HEIGHT FALLS AND A FEW WEAK
SHORTWAVES MOVING OVER THE FCST ARE ON THURS AND FRI. AT THE SFC...A
TRAILING COLD FRONT WILL MOVE INTO THE CWFA EARLY IN THE DAY AND
BRING A PLUME OF DEEPER MOISTURE WITH IT. MODELS INDICATE THAT THE
FRONT SHOULD BE MOVING OFF THE SE COAST BY LATE THURS/EARLY FRI WITH
ANOTHER CANADIAN SFC HIGH BRINGING WEAK NLY LOW LVL FLOW IN THE
FRONTS WAKE. OVER THE WEEKEND...AS THE HIGH MOVES NE OF THE
REGION...WINDS WILL LIKELY BECOME NEAR CALM AND THEN EVENTUALLY SLY
AS THE BERMUDA HIGH TRIES TO REGAIN ITS INFLUENCE. POPS AND QPF WERE
REDUCED A BIT ON THURS AS THE LATEST MODEL RUNS ARE SUGGESTING A
DRIER OVERALL FROPA. OTHERWISE...I STILL CARRY DIURNAL CHANCE TO
SLIGHT CHANCE POPS FOR FRI AND SLIGHT CHANCE FOR SAT AND SUN. I
BUMPED UP HIGH TEMPS A DEGREE OR 2 FOR THURS AND FRI WITH VALUES NOW
AROUND CLIMO. VALUES WILL LIKELY DROP A FEW DEGREES FOR SAT AND SUN
WITH LOWER THICKNESSES ANTICIPATED.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AT KCLT /21Z UPDATE/...A DEEP LAYER RIDGE OF HIGH PRESSURE WILL
REMAIN OVER THE REGION THROUGH THE VALID PERIOD OF THE TAF. THE
GRADIENT WILL WEAKEN AS THE CENTER OF THE RIDGE MOVES
OVERHEAD...RESULTING IN A LONG PERIOD OF CALM WINDS TONIGHT AND
MONDAY MORNING. WINDS THIS AFTN SHOULD REMAIN OUT OF THE NE AT
5-8KTS...WITH A FEW GUSTS TO 10-15 KT PER TDWR WINDS JUST OFF THE
SFC. SCT TO BKN CU IN THE 4-6KFT RANGE SHOULD PERSIST UNTIL AROUND 6
PM AT WHICH TIME THEY SHOULD DISSIPATE.
ELSEWHERE...THE WEATHER PATTERN IS THE SAME AS AT KCLT WITH SIMILAR
CONDITIONS AT THE OTHER AIRFIELDS. ONE POSSIBLE EXCEPTION IS AT
KAVL. THEY SHOULD FALL UNDER THEIR CROSSOVER TEMPERATURE LATER
TONIGHT. CERTAINLY PARTS OF THE FRENCH BROAD VALLEY WILL SEE
FOG...BUT IT/S NEVER AN EASY CALL AT KAVL. I LIKED THE MID SHIFT/S
2SM AND SCT005 SO I RETAINED THAT IN THE FORECAST.
OUTLOOK...A DRY PATTERN IS EXPECTED THROUGH TUESDAY AS HIGH PRESSURE
BUILDS IN FROM THE NORTH AND PERSISTS. MOISTURE WILL START TO RETURN
AHEAD OF A FRONT APPROACHING FROM THE NW DURING MID AND LATE WEEK.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% LOW 56% HIGH 86%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...MCAVOY/WIMBERLEY
SHORT TERM...JAT
LONG TERM...JPT
AVIATION...MCAVOY/WIMBERLEY
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
310 PM CDT SUN AUG 25 2013
.DISCUSSION...
NORTHWEST GULF OF MEXICO DEEP TROPICAL MOISTURE CONTINUES TO
SPREAD SLOWLY WESTWARD INTO THE TEXAS COAST AS UPPER LEVEL
RIDGING STRENGTHENS TO OUR NORTH. AS ANTICIPATED...ACTIVITY
OVER THE GULF WATERS IS WEAKENING/DISSIPATING THIS AFTERNOON
WHILE INLAND`S STRONGEST STORMS REMAIN GENERALLY CONFINED TO
NEAR AND SOUTH OF INTERSTATE 10. PREVIOUS FORECASTS FROM THE
LAST FEW DAYS THAT HAVE BEEN CALLING FOR UP TO AN INCH OR TWO
OF RAIN FROM SUNDAY THROUGH TUESDAY WITH THE GREATEST CONCENTRATION
ACROSS COASTAL COUNTIES AND ESPECIALLY OFFSHORE STILL LOOKS ON
TRACK WITH THE NEXT SET OF STORMS EXPECTED TO DEVELOP LATER THIS
EVENING AND ON THROUGH THE OVERNIGHT HOURS NEAR THE COAST AND JUST
OFFSHORE. ACTIVITY SHOULD WORK ITS WAY INLAND DURING THE DAY
TOMORROW...BUT THE GREATEST RAINFALL TOTALS ARE STILL ANTICIPATED
TO BE NEAR THE COAST AND OFFSHORE. ANOTHER NOT SO HOT LATE AUGUST
DAY IS EXPECTED UNDER ABUNDANT CLOUD COVER ON MONDAY. TUESDAY
SHOULD BE OUR LAST CHANCE OF RAIN FOR THE WEEK AS THIS SYSTEM
WORKS ITS WAY TO OUR WEST AND NORTHWEST AND UPPER LEVEL RIDGING
AND ASSOCIATED SUBSIDENCE BUILDS ACROSS SOUTHEAST TEXAS. THIS
PATTERN CHANGE TRANSLATES TO BACK TO NEAR NORMAL LATE AUGUST
TEMPERATURES FOR THE ENTIRE AREA. 42
&&
.MARINE...
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ALMOST ALL
DAY TODAY OVER THE WATERS. THIS IS IN RESPONSE TO A WEAK TROPICAL
WAVE WITH ITS AXIS LOCATED JUST SOUTH OF THE LAKE CHARLES AREA.
WINDS HAVE BEEN AROUND SCEC CRITERIA FOR THE NEARSHORE WATERS WHILE
BELOW CRITERIA PAST 20 NM. THE WAVE AXIS WILL CONTINUE TO NUDGE
WESTWARD TONIGHT AS A SHORTWAVE AT 500 MB APPROACHES. SHOWERS AND
THUNDERSTORMS WILL BE LIKELY MONDAY AND THEN BEGIN TO WANE EARLY
TUESDAY AS THE WAVE AXIS MOVES AWAY. 23
&&
.PREV DISCUSSION... /ISSUED 1251 PM CDT SUN AUG 25 2013/
DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.
AVIATION...
OVERVIEW...RAIN CONFINED TO THE COAST TODAY WITH MVFR DECKS ACROSS
MOST OF SOUTHEAST TEXAS. ANOTHER BAND OF RAIN HAS DEVELOPED ALONG
SOUTHERN LAKE CHARLES CWA BORDER AND IS MOVING TOWARDS THE WEST. A
VORTICITY MAXIMUM ASSOCIATED WITH A SHORTWAVE WILL APPROACH THE
COAST MONDAY. GFS/ NAM/ ECMWF HAVE THE FEATURE MOVING INLAND A
TAD BEFORE 11Z WITH THE RAP BEING THE MOST PROGRESSIVE BRINGING
THE SHORTWAVE IN AROUND 3Z MONDAY.
KCLL/KUTS/KCXO...RAIN SHOULD FOR THE MOST PART REMAIN SOUTH OF
THESE TAF SITES WITH MOSTLY BROKEN MVFR CLOUDS. LOOKS LIKE BULK OF
RAIN MONDAY WILL ALSO BE SOUTH OF THESE TAF SITES. A SLIGHT
DEVIATION IN THE TRACK OF THE SHORTWAVE COULD ALTER THE QPF FIELD
THOUGH. WILL HAVE TO CLOSELY MONITOR SITUATION AND ADJUST
ACCORDINGLY.
KIAH/KHOU...CHANCE FOR SCATTERED SHOWERS TO AFFECT THE TERMINALS
THIS AFTERNOON AS REDEVELOPMENT IS ALREADY OCCURRING OFF TO THE
EAST. MOSTLY LIKELY THESE SITES WILL REMAIN IN MVFR CIGS FOR MOST
OF TODAY. THERE MIGHT BE A SLIGHT BREAK THIS EVENING INTO EARLY
MORNING BEFORE THE NEXT ROUND OF CONVECTION APPROACHES. TIMING OF
THE SHORTWAVE IS AGAIN CRUCIAL HERE AS A SLIGHTLY MORE PROGRESSIVE
MOVING SHORTWAVE WOULD FAVOR RAIN STARTING AROUND 6Z WITH THE
GLOBAL MODELS BEING MUCH SLOWER WITH THE TIMING OF THE RAINFALL.
KLBX/KSGR/KGLS...PRECIP IN ONGOING AT KGLS WITH PRECIP LIKELY AT
KLBX AND KSGR. THESE SITES WILL BE THE FIRST LOCATIONS TO SEE THE
RAINFALL MONDAY MORNING ALSO AS THE SHORTWAVE MOVES IN FROM THE
EAST.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 74 96 75 / 20 30 10 20 10
HOUSTON (IAH) 75 90 75 95 75 / 30 40 20 30 10
GALVESTON (GLS) 79 88 80 91 81 / 60 60 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 10 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1251 PM CDT SUN AUG 25 2013
.DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.
&&
.AVIATION...
OVERVIEW...RAIN CONFINED TO THE COAST TODAY WITH MVFR DECKS ACROSS
MOST OF SOUTHEAST TEXAS. ANOTHER BAND OF RAIN HAS DEVELOPED ALONG
SOUTHERN LAKE CHARLES CWA BORDER AND IS MOVING TOWARDS THE WEST. A
VORTICITY MAXIMUM ASSOCIATED WITH A SHORTWAVE WILL APPROACH THE
COAST MONDAY. GFS/ NAM/ ECMWF HAVE THE FEATURE MOVING INLAND A
TAD BEFORE 11Z WITH THE RAP BEING THE MOST PROGRESSIVE BRINGING
THE SHORTWAVE IN AROUND 3Z MONDAY.
KCLL/KUTS/KCXO...RAIN SHOULD FOR THE MOST PART REMAIN SOUTH OF
THESE TAF SITES WITH MOSTLY BROKEN MVFR CLOUDS. LOOKS LIKE BULK OF
RAIN MONDAY WILL ALSO BE SOUTH OF THESE TAF SITES. A SLIGHT
DEVIATION IN THE TRACK OF THE SHORTWAVE COULD ALTER THE QPF FIELD
THOUGH. WILL HAVE TO CLOSELY MONITOR SITUATION AND ADJUST
ACCORDINGLY.
KIAH/KHOU...CHANCE FOR SCATTERED SHOWERS TO AFFECT THE TERMINALS
THIS AFTERNOON AS REDEVELOPMENT IS ALREADY OCCURRING OFF TO THE
EAST. MOSTLY LIKELY THESE SITES WILL REMAIN IN MVFR CIGS FOR MOST
OF TODAY. THERE MIGHT BE A SLIGHT BREAK THIS EVENING INTO EARLY
MORNING BEFORE THE NEXT ROUND OF CONVECTION APPROACHES. TIMING OF
THE SHORTWAVE IS AGAIN CRUCIAL HERE AS A SLIGHTLY MORE PROGRESSIVE
MOVING SHORTWAVE WOULD FAVOR RAIN STARTING AROUND 6Z WITH THE
GLOBAL MODELS BEING MUCH SLOWER WITH THE TIMING OF THE RAINFALL.
KLBX/KSGR/KGLS...PRECIP IN ONGOING AT KGLS WITH PRECIP LIKELY AT
KLBX AND KSGR. THESE SITES WILL BE THE FIRST LOCATIONS TO SEE THE
RAINFALL MONDAY MORNING ALSO AS THE SHORTWAVE MOVES IN FROM THE
EAST.
23
&&
.PREV DISCUSSION... /ISSUED 1029 AM CDT SUN AUG 25 2013/
DISCUSSION...
DEEP MOISTURE CONTINUES TO SLOWLY FILTER INTO SOUTHEAST TEXAS
FROM THE EAST THIS MORNING IN ASSOCIATION WITH A NORTHWESTERN
GULF OF MEXICO DISTURBANCE. PER WATER VAPOR SATELLITE LOOP...
A MUCH DRIER AIR MASS IS MOVING INTO THE NORTHERN PORTIONS OF
OUR AREA...AND THIS IS EXPECTED TO KEEP THE MAJORITY OF SPOTS
GENERALLY ALONG AND NORTH OF INTERSTATE ON THE DRY SIDE TODAY.
RECENT RADAR TRENDS HAVE ACTIVITY WEAKENING NEAR THE COAST AND
OFFSHORE...SO HAVE MADE SOME DOWNWARD POP ADJUSTMENTS TO AREA
FORECASTS FOR THE REST OF THE DAY. ALSO...SHAVED OFF SEVERAL
DEGREES FROM THIS AFTERNOON`S HIGH TEMPERATURES BASED ON THE
ANTICIPATED EXTRA CLOUD COVER. 42
PREV DISCUSSION... /ISSUED 419 AM CDT SUN AUG 25 2013/
DISCUSSION...
ONGOING FCST HAS BEEN LEFT LARGELY UNCHANGED. DEEPER MOISTURE IS
MOVING INTO THE UPPER TEXAS COASTAL WATERS AND COUNTIES FROM THE
EAST. EXPECT PERIODS OF SHRA/TSRA ACROSS THE SRN PARTS OF THE
REGION THRU THE DAY WITH BEST COVERAGE SOUTH OF I-10. DID KNOCK
POPS DOWN ACROSS FAR NORTHERN COUNTIES WHERE COMPETITION FROM
UPPER RIDGE IS MORE PRONOUNCED. WE`LL PROBABLY SEE A BREAK IN MOST
PRECIP LATE IN THE AFTN AND EARLY THIS EVENING FOLLOWED BY
WIDESPREAD REDEVELOPMENT OFFSHORE AND ALONG THE COAST TONIGHT AND
MON MORNING. COVERAGE WILL THEN GRADUALLY EXPAND INLAND INTO THE
SW HALF OF THE REGION DURING THE DAY. EXPECTING THE BEST COVERAGE
IN THE COUNTIES SW/W OF THE METRO AREA (THAT NEED THE RAINFALL THE
MOST).
CHANCES OF RAINFALL WILL DIMINISH ON TUE/WED AS MOISTURE AXIS
GRADUALLY PUSHES OUT OF THE REGION. BY LATE WED & THURS RAIN
CHANCES WILL BE CLOSE TO NIL AS PW`S DROP AND UPPER RIDGE REALLY
REESTABLISHES ITSELF OVERHEAD. TEMPS SHOULD CLIMB BACK INTO THE
UPPER 90S TO NEAR 100 AT SOME LOCATIONS DURING THE 2ND HALF OF THE
WEEK. 47
TROPICS...
NHC IS WATCHING THE WAVE OFF THE YUCATAN COAST AND CURRENTLY
GIVING IT A 60% CHANCE OF DEVELOPMENT. THIS SYSTEM WILL MOST
LIKELY NOT AFFECT SE TX WX AND PROBABLY BE A MEXICO ISSUE. 47
MARINE...
CONVECTION SLATED TO INCREASE/MOVE INTO THE AREA TODAY AS THE WEAK
TROPICAL WAVE EDGES CLOSER. THIS SYSTEM WILL ALSO HELP TO SLIGHTLY
INCREASE WINDS OVER THE COASTAL WATERS AND HAVE ISSUED SMALL CRAFT
EXERCISE CAUTION FLAGS FOR THIS AFTN. THESE FLAGS MIGHT NEED TO BE
EXTENDED INTO TONIGHT. THESE STRONGER EASTERLY WINDS MAY ALSO HAVE
IMPACTS ON LOCAL TIDES (WHICH ARE CURRENTLY RUNNING ABOUT 1-1.5 FT
ABOVE NORMAL). 41
AVIATION...
PER SHORT-RANGE MODELS WE SHOULD HAVE A VERY DISTINCT LINE OF HAVE
AND HAVE NOTS WITH RESPECT TO PCPN. THE BOUNDARY LOOKS TO BE RIGHT
ALONG I-10. AS SUCH NO REAL ARGUMENTS WITH THE GOING TAF SET UP OF
KEEPING THE MENTION OF VCTS PRIMARILY SOUTH OF HOU. WILL HAVE SOME
ISSUES WITH SUN NIGHT/OVERNIGHT INTO MON WITH THE RE-START OF PCPN
AS THE WEAK TROPICAL WAVE CONTINUES TO AFFECT OUR WX. 41
SMOKE...
ERLY TRANSPORT WINDS WILL CONTINUE TO BRING SOME SMOKE INTO THE
HOUSTON/GALVESTON & SURROUNDING AREAS FROM AN ONGOING WILDFIRE IN
SOUTHERN JEFFERSON COUNTY (NEAR CLAM LAKE). HOPEFULLY THIS FIRE
WILL ENCOUNTER SOME RAINFALL TODAY AND LESSEN IMPACTS.
BUT...YES...THAT`S WHAT MANY OF US ARE SEEING AND SMELLING THIS
MORNING. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 74 96 75 / 20 30 10 20 10
HOUSTON (IAH) 75 90 75 95 75 / 30 40 20 30 10
GALVESTON (GLS) 79 88 80 91 81 / 60 60 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 10 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS SPOKANE WA
237 PM PDT Sun Aug 25 2013
.SYNOPSIS...
The moist southwest flow the region has been in over the past week
or so will once again bring the chance for showers and
thunderstorms this afternoon into the overnight hours. As we move
into the work week precipitation chances will diminish with only the
higher terrain having a decent chance for activity. Another
weather system over the weekend will raise chances for widespread
precipitation once again.
&&
.DISCUSSION...
Tonight through Monday evening: The big picture includes a large
ridge of high pressure centered near Missouri and a large trof of
low pressure over the northeast Pacific. The semi-permanent trof
has been providing the Pacific Northwest with a busy
pattern...namely disturbances rotating around the base and
bringing enhanced chances of precipitation to the region. The most
recent upper level wave is evident on water vapor satellite
imagery moving inland near the California/Oregon coast. Clouds are
streaming ahead of this system throughout the inland northwest.
More importantly showers and thunderstorms are developing over
Oregon that will migrate toward the inland northwest this evening.
Overnight convection: isolated to scattered thunderstorms (some
severe this afternoon) in Oregon will eventually morph into a
large rain shield with embedded thunderstorms as it moves into
central and eastern Washington. The concern with our thermal
profile is the potential for a gust front along and ahead of the
line of storms. The latest runs of the HRRR support this with a
large band of rain and possible gust front heading north across
the state late this evening through the late night hours. We have
increased our chances of precipitation with this feature as well
as added wording about the potential for gusty winds. With each
run of the HRRR, the speeds of the storms are increasing so will
have to monitor close this evening and update as necessary. Still
some weak elevated instability remains on the back side of the
wave so a few showers still possible overnight.
Monday: Weather pattern quiets down for most of the region as the
next wave approaches Monday. The majority of the energy associated
with this wave will affect the northwest part of the state leaving
the inland northwest under partly cloudy skies with just a few
showers and thunderstorms possible in the afternoon and evening.
The exception will be near the Cascade crest where scattered
showers and isolated thunderstorms will again develop in the
afternoon and evening hours. The relatively quick storm motion
with these storms as well as tonights activity will minimize the
threat of flooding. Precipitable water values remain 120-180% of
normal for this time of the year so what isolated activity does
develop will be wet...minimizing the potential for dry lightning
strikes. /AB
Monday Night through Thursday Evening...The Inland Northwest will be
sandwiched between the trough of low pressure moving south toward
along the BC coast and a hefty ridge of high pressure anchored
over the central portion of the country. The tug-of-war will be
pulled to the slightly retrograding ridge for Tuesday and
especially Wednesday, and the temperature forecast shows this with
readings 5 to 8 degrees above normal by midweek. After that, a
disturbance rounding the trough will begin the breakdown of the
ridge for our region, and opening the door for the weekend system
to follow on its heels. Cooling temperatures closer to normal
Thursday also look likely as a front traverses eastern Washington
and the Idaho panhandle.
As far as precipitation goes, the Cascades should remain under the
influence of the trough and any minor shortwave that moves over
western Washington Tuesday and Wednesday. Precipitation chances
were not changed much from previous forecasts, which keeps slight
chances along and just east of the crest. Farther east, there may
be a few showers/thunderstorms that move north in the monsoonal
flow, although these chances look to be highest south and east of
the ID panhandle. As the shortwave on Thursday moves east,
slightly higher chances will exist over mainly the higher terrain,
although some of the precipitation may move into the valleys. ty
Thursday Night through Saturday Night: Starting the period we will
be in the never ending SW flow that will continue to bring chances
of showers and t-storms mainly in the higher elevations. The
system will send a final frontal wave through Friday afternoon into
the overnight that will bring a good chance for rain and
thunderstorms for the Cascades...the NE Mtns of WA and the ID
Panhandle. Models are finally showing the persistent trough and
associated low pressure system will eject into the region next
weekend. Where models lack consistency is the track and exact
timing of the system passage. The GFS would bring the system
onshore on the Oregon coast whereas the EC would bring it onshore
on the Washington coast. Regardless the region will see widespread
rain showers and the threat for thunderstorms. Models are showing
a pretty good amount of associated moisture with the system and
when it reaches the Cascades rain will be expected. With the
Cascades expected to receive a fair amount of rain we will have
to monitor the area for Hydrology concerns. With the exit of the
system comes more uncertainties...the EC quickly exits the system
Monday whereas the GFS has the system stall over the region
bringing a much more prolonged period of precipitation. With the
event still almost a week away we have time to refine the
details...but overall next weekend looks to be wet.
Concerning other aspects of the forecast...winds look to kick up
during the daytime periods but should not bring any problems.
Temperatures will be cooling down as our flow shifts to more
westerly rather than the southwest flow. As of right now
temperatures look to drop back into the 70s and 80s by the weekend.
/Fliehman
&&
.AVIATION...
18Z TAFS: Shower activity diminished this morning with VFR and
light winds prevailing for all TAF locations. Minor diurnal wind
shifts expected late this morning through the early afternoon
hours as a more potent short wave approaches the region from the
southwest. This wave will bring a renewed threat of showers and
thunderstorms overnight. Updated from prob30 to tempo for chances
of showers tonight and may have to add a new FM group with later
updates to capture the onset of precipitation. Ceiling and
visibility generally expected to remain high with the exception
of the stronger thunderstorms embedded within tonights activity.
/Brown
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 59 79 58 83 60 88 / 50 20 10 10 10 10
Coeur d`Alene 57 79 55 83 57 88 / 50 20 10 10 10 10
Pullman 51 80 51 85 52 88 / 50 20 10 10 10 10
Lewiston 62 87 62 92 63 95 / 40 20 10 10 10 10
Colville 55 82 53 86 53 91 / 40 20 20 10 10 10
Sandpoint 53 77 50 81 50 86 / 50 20 20 10 10 10
Kellogg 56 78 56 83 56 86 / 50 20 20 10 10 10
Moses Lake 59 82 58 86 59 89 / 30 20 10 10 10 10
Wenatchee 62 81 62 85 64 88 / 40 20 10 10 10 10
Omak 60 82 58 85 59 89 / 30 30 20 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 PM CDT SUN AUG 25 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 346 PM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT
THROUGH TUESDAY AND HEAT INDEX VALUES.
LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM
SOUTHEAST NORTH DAKOTA THROUGH NORTHERN MINNESOTA...STRETCHING
EAST OVER SOUTHERN LAKE SUPERIOR. WATER VAPOR IMAGERY AND RAP 500 MB
ANALYSIS SHOWED HIGH PRESSURE CENTERED ALONG THE KANSAS/MISSOURI BORDER
WITH A FLATTENING RIDGE EXTENDING NORTH INTO THE UPPER MISSISSIPPI RIVER
VALLEY. A FEW SUBTLE SHORTWAVES NOTED...THE FIRST WAS LOCATED OVER
THE EASTERN DAKOTAS AND ANOTHER...SLIGHTLY STRONGER WAVE...WAS
MOVING INTO EASTERN MONTANA. THE WARM FRONT AND THESE TWO WAVES WILL
BE THE MAIN FEATURES TO KEEP A CLOSE EYE ON THROUGH MONDAY MORNING.
ALSO...A PLUME OF MONSOONAL MOISTURE WAS STREAMING NORTHWARD THROUGH
THE DESERT SOUTHWEST AND INTO WESTERN NEBRASKA/SOUTH DAKOTA...HEADING EAST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE WARM FRONT THIS
EVENING...THEN MOVE SOUTHWARD OVERNIGHT. IT APPEARS THAT THE STORMS
WILL INITIATE OVER EAST CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN
THEN SHIFT SOUTHWARD WITH TIME DURING THE OVERNIGHT HOURS
POTENTIALLY IMPACTING AREAS NORTH OF INTERSTATE 90. CAPE VALUES
ARE RATHER IMPRESSIVE LATE THIS AFTERNOON OVER THESE AREAS...WITH
TEMPERATURES IN THE UPPER 90S AND DEWPOINTS IN THE LOWER 70S
PRODUCING 3500 TO 4000 J/KG OF SURFACE BASED CAPE. SHEAR ISN/T
OVERLY IMPRESSIVE WITH 0-6KM BULK SHEAR VALUES OF AROUND 30
KTS...MAINLY NORTH OF INTERSTATE 94. HOWEVER...THE SHEAR IS FOCUSED
IN THE 0-3 KM LAYER WHICH WOULD FAVOR THE POTENTIAL FOR LINEAR STORM
STRUCTURES WITH DAMAGING WINDS. THE HIGH INSTABILITY OVER THE AREA
SHOULD OVERCOME THE LACK OF STRONG SHEAR...LEADING TO THE POTENTIAL
FOR SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS. STRONG
850 MB MOISTURE TRANSPORT FOCUSES INTO THE WARM FRONT TONIGHT WHICH
COULD POTENTIALLY LEAD TO REPEATED ROUNDS OF THUNDERSTORMS ALONG IT.
PRECIPITABLE WATER VALUES INCREASE TO 2.0 TO 2.3 INCHES
TONIGHT...WHICH IS AROUND 230 PERCENT OF NORMAL. ALSO...WARM CLOUD
DEPTHS INCREASE TO AROUND 4.7 KM. ANY THUNDERSTORMS THAT DEVELOP IN
THIS AIRMASS WILL BE VERY EFFICIENT RAIN PRODUCERS. THESE FACTORS
COULD LEAD TO FLASH FLOODING OVER PORTIONS OF NORTHERN AND NORTH
CENTRAL WISCONSIN TONIGHT INTO EARLY MONDAY MORNING. CONFIDENCE ON
SEVERE THUNDERSTORM POTENTIAL IS HIGHEST NORTH AND EAST OF INTERSTATE
94 TONIGHT. A STRONG CAP ALONG AND SOUTH OF THESE AREAS SHOULD LIMIT
HOW FAR SOUTH CONVECTION CAN BUILD. CANNOT RULE OUT THE STORMS
MAKING IT TO THE INTERSTATE 90 CORRIDOR BUT THEY SHOULD QUICKLY
DISSIPATE IF THEY MAKE IT ANY FURTHER SOUTH AND ENCOUNTER THE
STRONG CAP.
SHOWERS AND STORMS SHOULD QUICKLY TAPER OFF EARLY MONDAY MORNING AS
MOISTURE TRANSPORT WEAKENS. DEPENDING ON HOW THE OVERNIGHT
CONVECTION PLAYS OUT...THE WARM FRONT LOOKS TO BE ORIENTED JUST
NORTH OF THE INTERSTATE 94 CORRIDOR BY LATE MONDAY MORNING INTO
MONDAY AFTERNOON. MLCAPE VALUES INCREASE INTO THE 2000 TO 3500 J/KG
RANGE ALONG THE FRONT BY MID AFTERNOON ON MONDAY. 0-6 KM BULK SHEAR
VALUES HOVER AROUND 30 KTS OVER MUCH OF NORTHERN AND CENTRAL
WISCONSIN MONDAY AFTERNOON INTO MONDAY EVENING WHICH WOULD FAVOR
SEVERE MULTICELL STORMS. WITH THE HIGH CAPE VALUES NEAR THE WARM
FRONT...CANNOT RULE OUT A FEW SUPERCELL STRUCTURES ESPECIALLY OVER
NORTHWEST INTO NORTH CENTRAL WISCONSIN. ALSO FORECAST MODELS SUGGEST
THERE COULD BE JUST ENOUGH 0-1 KM SHEAR TO SUPPORT AN ISOLATED
TORNADO OR TWO NEAR THE WARM FRONT. OTHERWISE...THE STORMS WILL BE
CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND HEAVY
RAINFALL. THE SHOWERS AND STORMS WILL CONTINUE INTO MONDAY NIGHT
WITH THE HIGHEST CHANCES MAINLY ALONG AND NORTHEAST OF INTERSTATE
94.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 346 PM CDT SUN AUG 25 2013
SHOWERS AND STORMS WILL BE ONGOING TUESDAY MORNING...MAINLY ALONG
AND EAST OF THE MISSISSIPPI RIVER. A WEAK COLD FRONT IS EXPECTED TO
SWEEP ACROSS THE REGION TUESDAY AFTERNOON. A FEW SHOWERS AND STORMS
CANNOT BE RULED OUT ALONG THE FRONT TUESDAY AFTERNOON INTO TUESDAY
EVENING...BUT IT APPEARS A CAP WILL HOLD STRONG FOR AREAS WEST OF
THE MISSISSIPPI RIVER...WITH A CHANCE OF SHOWERS AND STORMS OVER MUCH
OF WESTERN INTO CENTRAL WISCONSIN. 925MB TEMPERATURES COOL INTO THE
22 TO 25 C RANGE IN THE WAKE OF THE FRONT. SO WE SHOULD SEE A VERY
SMALL RELIEF FROM THE HEAT WITH HEAT INDEX VALUES FALLING INTO THE
MID TO UPPER 90S. SURFACE HIGH PRESSURE SETTLES OVERHEAD ON THURSDAY
BRINGING SOME SLIGHTLY COOLER AIR WITH IT...WITH 925MB TEMPERATURES
FALLING TO AROUND 23 C...PRODUCING HIGHS IN THE UPPER 80S TO AROUND
90. THE HIGH SLIDES OFF TO THE EAST ON FRIDAY AS A WARM FRONT PUSHES
EAST OUT OF THE NORTHERN/CENTRAL PLAINS. WEAK SHORTWAVES ARE EXPECTED
TO INTERACT WITH THE FRONT BRINGING CHANCES FOR SHOWERS AND STORMS TO
THE AREA FROM THURSDAY AFTERNOON THROUGH FRIDAY NIGHT. MODEL
SOLUTIONS START TO DIVERGE SATURDAY INTO SUNDAY ON TIMING OF THESE
SHORTWAVES SO CONFIDENCE LOW ON PRECIPITATION CHANCES SATURDAY INTO
SUNDAY. TEMPERATURES ARE EXPECTED TO WARM SLIGHTLY FOR THE WEEKEND
WITH HIGHS CLIMBING INTO THE UPPER 80S TO LOWER 90S...DEPENDING ON
TIMING OF THE SHORTWAVES AND ANY SHOWERS AND STORM ASSOCIATED WITH
THEM. 850MB TEMPERATURE STANDARDIZED ANOMALIES HOVER AROUND PLUS 2
THIS WEEKEND THROUGH EARLY NEXT WEEK SO WILL HAVE TO KEEP A CLOSE
WATCH ON THE POTENTIAL FOR HEAT HEADLINES WITH THE POSSIBILITY OF
SEEING NEAR RECORD HEAT FOR THESE DATES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1215 PM CDT SUN AUG 25 2013
BREEZY SOUTHWEST WINDS TO CONTINUE THROUGH EARLY THIS EVENING
BEFORE SUBSIDING AFTER SUNSET...OTHERWISE VFR CONDITIONS WILL
PREVAIL. ATTENTION THEN TURNS TO INCREASING CONFIDENCE OF A
THUNDERSTORM COMPLEX DEVELOPING ACROSS CENTRAL MN INTO NORTHWEST
WI THIS EVENING...THEN MOVING SOUTHEAST THROUGH THE AREA
OVERNIGHT/EARLY MONDAY MORNING. QUESTION WILL BE HOW FAR SOUTH
THIS COMPLEX OF STORMS GETS/POTENTIAL OF AFFECTING TAF SITES/ BEFORE
SHUNTING EAST MONDAY MORNING. FOR NOW...HAVE CONTINUED A VCTS
MENTION AT KRST/KLSE TAF SITES IN THE 09-15Z TIME FRAME. MODEL
SOUNDINGS SHOWING THAT THIS CONVECTION/STORMS WILL BE ELEVATED IN
NATURE WITH CLOUD BASES GENERALLY AOA 8KFT. LOOKING FOR THIS
COMPLEX OF STORMS TO SHIFT EAST OF THE AREA AFTER 15Z WITH VFR
CONDITIONS EXPECTED.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ079-
086>088-094>096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...DAS
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1215 PM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1215 PM CDT SUN AUG 25 2013
BREEZY SOUTHWEST WINDS TO CONTINUE THROUGH EARLY THIS EVENING
BEFORE SUBSIDING AFTER SUNSET...OTHERWISE VFR CONDITIONS WILL
PREVAIL. ATTENTION THEN TURNS TO INCREASING CONFIDENCE OF A
THUNDERSTORM COMPLEX DEVELOPING ACROSS CENTRAL MN INTO NORTHWEST
WI THIS EVENING...THEN MOVING SOUTHEAST THROUGH THE AREA
OVERNIGHT/EARLY MONDAY MORNING. QUESTION WILL BE HOW FAR SOUTH
THIS COMPLEX OF STORMS GETS/POTENTIAL OF AFFECTING TAF SITES/ BEFORE
SHUNTING EAST MONDAY MORNING. FOR NOW...HAVE CONTINUED A VCTS
MENTION AT KRST/KLSE TAF SITES IN THE 09-15Z TIME FRAME. MODEL
SOUNDINGS SHOWING THAT THIS CONVECTION/STORMS WILL BE ELEVATED IN
NATURE WITH CLOUD BASES GENERALLY AOA 8KFT. LOOKING FOR THIS
COMPLEX OF STORMS TO SHIFT EAST OF THE AREA AFTER 15Z WITH VFR
CONDITIONS EXPECTED.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ079-
086>088-094>096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1147 AM CDT SUN AUG 25 2013
UPDATED UPDATE/AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...
ISSUED AT 1129 AM CDT SUN AUG 25 2013
LATEST MESO ANALYSIS INDICATED THINGS WERE SETTING UP ACROSS
NORTHERN WISCONSIN AND UPPER MICHIGAN LATE THIS MORNING. SURFACE
BASED CAPES WERE ALREADY BETWEEN 2000 AND 3000 J/KG...DCAPES WERE
AT 1000/1500 J/KG AND LIFTED INDICES OF -4 TO -6 C AND 0-6KM SHEAR
OF 30 TO 35 KNOTS. ALSO...IMPRESSIVE POOLING OF DEW POINTS AROUND
850MB...ALONG WITH MOISTURE CONVERGENCE NOTED ON THE SPC MESOANALYSIS
PAGE.
INCREASING LOW LEVEL JET LATER THIS AFTERNOON ALONG WITH ALL THE
HEAT AND HUMIDITY WILL PROVIDE AMPLE SUPPORT FOR STRONG TO SEVERE
THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON OR EARLY THIS EVENING
ACROSS NORTHERN WISCONSIN. THE STORMS WILL GRADUALLY SAG SOUTHWARD
ACROSS THE REMAINDER OF THE AREA DURING THE EVENING INTO EARLY
MONDAY MORNING. MODIFIED SOUNDINGS AT RHINELANDER INDICATED 3000
TO 3500 J/KG OF CAPE...WET BULB HEIGHTS NEAR TWELVE THOUSAND FEET
AND WINDEX VALUES OF 45 TO 55 KNOTS. DESPITE BEING LATER IN THE
EVENING OR EARLY MONDAY MORNING...ENOUGH 0-6 KM SHEAR SUPPORT THE
POTENTIAL FOR SOME DAMAGING WINDS OR LARGE HAIL ACROSS THE FOX
VALLEY AND LAKESHORE REGION. ALSO...TORRENTIAL RAIN WILL BE ACCOMPANIED
BY SOME OF THE STORMS THAT COULD PRODUCE LOCALIZED FLOODING.
LOOKING AHEAD TO MONDAY...CONVECTION TONIGHT COULD HAVE A BIG IMPACT
ON MAXIMUM TEMPERATURES WHICH IS PROBLEMATIC FOR HEAT HEADLINES. WILL
NEED TO ASSESS THIS FOR THE AFTERNOON PACKAGE.
.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 500 AM CDT SUN AUG 25 2013
UPPER RIDGE CONTINUES TO FLATTEN OVER THE WESTERN GREAT LAKES AS
SHORT WAVE IMPULSE MOVES EAST ACROSS NORTHERN LAKE SUPERIOR THIS
MORNING. FOR THE MOST PART...SHORT RANGE MODELS INCLUDING THE HRRR
AND RAP DID A RATHER LOUSY JOB HANDLING STRONGER CONVECTION NORTH
OF WISCONSIN...AS WELL AS LIGHTER SCATTERED SHOWER ACTIVITY MOVING
ACROSS CENTRAL AND NORTHERN WISCONSIN EARLY THIS MORNING. SCATTERED
SHOWER AND ISOLATED THUNDERSHOWER ACTIVITY OVER THE FORECAST AREA
APPEARS TO BE ASSOCIATED WITH VERY WEAK UPPER-LEVEL IMPULSE...MODEST
WAA AND NEAR EASTERN EDGE OF ROBUST CAP EXTENDING FROM CENTRAL
MINNESOTA INTO NORTHWEST WISCONSIN. THIS ACTIVITY WILL CONTINUE TO
PUSH ACROSS THE FORECAST AREA THIS MORNING AND SHOULD REMAIN
SCATTERED AND LIGHT IN INTENSITY. ACTIVITY EXPECTED TO BE EAST OF
THE FORECAST AREA BY AROUND 15Z.
LOOKING FARTHER UPSTREAM...MORE SCATTERED THUNDERSTORM ACTIVITY
HAS DEVELOPED OVER WESTERN MINNESOTA AHEAD OF FRONTAL BOUNDARY
OVER THE DAKOTAS. MAJORITY OF THE GUIDANCE SUGGESTS THAT THIS
ACTIVITY WILL BEGIN TO SINK MORE SSE ACROSS CENTRAL MINNESOTA
LATER THIS MORNING AND GRADUALLY WEAKEN AS IT CONTINUES TO
PROPAGATE AWAY FROM FRONTAL BOUNDARY. HOWEVER LATEST RADAR TRENDS
SHOWING MORE OF AN EASTWARD MOVEMENT AND IF THIS ACTIVITY HOLDS
TOGETHER IT MAY IMPACT THE NORTHWEST PORTION OF THE FORECAST AREA
LATE THIS MORNING. WILL NEED TO KEEP AN EYE ON THIS ACTIVITY THIS
MORNING. FOR NOW WILL STICK TO CURRENT THINKING THAT THIS
ACTIVITY SHOULD WEAKEN BEFORE IT REACHES THE FORECAST AREA. THUS
IT APPEARS THAT FORECAST AREA STILL ON TRACK FOR A HOT AND
INCREASINGLY HUMID DAY. DID NOT MAKE ANY CHANGES TO PREVIOUS MAX
TEMPERATURE FORECAST FOR TODAY THUS STILL EXPECT TEMPS TO REACH
THE 90-95 DEGREE RANGE OVER THE WESTERN PORTION OF THE FORECAST
AREA WITH READINGS NEAR 90 ACROSS THE NORTH WOODS. DID ADJUST
DEW POINTS DOWN A DEGREE OR TWO THIS AFTERNOON WITH ANTICIPATED
AFTERNOON MIXING. THUS HEAT INDICES WILL BE GENERALLY IN 95 TO 100
DEGREE RANGE WITH HIGHEST VALUES OVER THE WESTERN PORTION OF THE
FORECAST AREA THIS AFTERNOON.
FOR THIS EVENING AND TONIGHT...QUESTION THEN BECOMES WHEN AND
WHERE THUNDERSTORM ACTIVITY WILL FIRE AS SHORTWAVE IMPULSE HEADS
EAST TOWARD THE WESTERN GREAT LAKES AND FRONTAL BOUNDARY
APPROACHES. ALTHOUGH THERE HAS BEEN A VARIETY OF SOLUTIONS AS TO
HOW THE SCENARIO WILL PLAY OUT...SEEMS THAT A WEAK CONSENSUS OF
THE GUIDANCE SUGGESTS THAT THUNDERSTORM ACTIVITY WILL DEVELOP NEAR
THE WISCONSIN-MICHIGAN BORDER...ALONG AND AHEAD OF FRONTAL
BOUNDARY FORECAST TO DRIFT SSE INTO NORTHERN WISCONSIN THIS
EVENING. THIS BOUNDARY MAY ALSO GET SOME REINFORCEMENT FROM LAKE
SUPERIOR BREEZE. THIS ACTIVITY SHOULD THEN SAG SOUTHWARD ACROSS
THE FORECAST AREA OVERNIGHT INTO MONDAY MORNING. SHOULD BE PLENTY
OF INSTABILITY OVER THE FORECAST AREA SUNDAY EVENING WITH MLCAPES
AROUND 3000 J/KG. BEST DEEP LAYER SHEAR TO SUSTAIN UPDRAFTS WILL
BE OVER THE NORTHERN HALF OF THE FORECAST AREA. SPC ADDED MOST
OF THE FORECAST AREA INTO A SLIGHT RISK FOR SEVERE LATE THIS
AFTERNOON AND INTO THE LATE EVENING HOURS WHICH SEEMS REASONABLE.
PRIMARY THREAT APPEARS TO BE DAMAGING WINDS AND PERHAPS SOME
LARGE HAIL. MODELS VARY AS TO THE TIMING THE CONVECTION WILL
FIRE...BEST GUESS IS SOMETIME IN THE 23-02Z TIME FRAME WITH
ACTIVITY MOVING SOUTH OR SOUTHEAST ACROSS THE FORECAST AREA TOWARD
MIDNIGHT. WILL ALSO NEED TO KEEP AN EYE ON A LOCALLY HEAVY
RAINFALL THREAT...ESPECIALLY IF ACTIVITY CAN TRAIN FROM WEST TO
EAST ALONG FRONTAL BOUNDARY LATER TONIGHT.
MORE UNCERTAINTY FOR MONDAY AS MODELS DIVERGE ON HOW LONG ACTIVITY
WILL PERSIST ALONG FRONTAL BOUNDARY EXPECTED TO BE LOCATED
SOMEWHERE OVER NORTHERN WISCONSIN. LOCATION OF RESIDUAL
THUNDERSTORM OUTFLOW IS ALSO A FACTOR AS TO WHERE ADDITIONAL
CONVECTION MAY FIRE AGAIN DURING THE DAY ON MONDAY. FOR NOW KEPT
BROAD BRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST AREA. MAX TEMPS
ON MONDAY WILL BE DEPENDENT ON RESIDUAL CLOUD
COVER...PRECIPITATION AND LOCATION OF FRONTAL BOUNDARY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 501 AM CDT SUN AUG 25 2013
WHILE THE CNTRL CONUS UPR RDG TO REMAIN THE MAIN WEATHER FEATURE
THRU MUCH OF THE UPCOMING WEEK...ITS SLOW RETROGRESSION FROM THE
MID-MS VALLEY TO THE CNTRL HI PLAINS WL ALLOW THE MEAN FLOW TO
TURN NW BY THU AND BRING SLIGHTLY COOLER/DRIER CONDITIONS TO NE
WI. MAIN FCST EMPHASIS TO BE THRU MID-WEEK AS A FRONTAL BOUNDARY
MOVES THRU AN UNSTABLE AIR MASS AND SETS THE STAGE FOR TSTMS. A
FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH LOCALLY HEAVY
RAINFALL. TEMPS TO REMAIN WELL ABOVE NORMAL TIL FURTHER NOTICE...
ESPECIALLY THRU THU.
PLENTY OF QUESTIONS LINGER FOR TUE STARTING WITH WHERE (IF) MON
NGT`S CONVECTION TO BE LOCATED...WHERE THE NRN WI FRONTAL BOUNDARY
TO RESIDE...WL ADDITIONAL PCPN DEVELOP ON THE EDGE OF THE CAP AND
COULD ANY OF THESE STORMS TURN SEVERE? THE KEY APPEARS TO BE THE
MON NGT CONVECTION SINCE IF IT WERE TO DEVELOP...MORE CLOUDS AND
BRIEF STABILIZATION WOULD OCCUR. IF THIS CONVECTION STAYS TO THE
NORTH...THIS WOULD ALLOW TEMPS TO SOAR ONCE AGAIN AND ALLOW THE
ATMOSPHERE TO REALLY DESTABILIZE BY THE AFTERNOON. TO TOP ALL OF
THIS OFF...THE MDLS BRING A WEAK SFC TROF INTO WI. HARD TO FATHOM
NOT SEEING ANY PCPN MON NGT...THUS HAVE SIDED WITH MENTIONING A
HIGHER POP ON TUE ACROSS FAR NE WI WHERE THE WEAKER CAP WL EXIST.
SEVERE POTENTIAL TO BE DICTATED BY HOW WARM WE CAN GET AND WHETHER
THAT APPROACHING WEAK SFC TROF CAN GENERATE ENUF LIFT TO BREAK THE
CAP. IF THE CAP IS BROKEN...WE COULD SEE A ROUND OF STRONG TO
SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS AND TORRENTIAL
DOWNPOURS.
SHWR/TSTM THREAT WOULD CARRYOVER INTO TUE EVENING UNTIL THE SFC
TROF EXITS THE AREA AND A WEAK AREA OF HI PRES BEGINS TO BUILD
ACROSS THE UPR MS VALLEY. ONLY CHANGE TO THIS PART OF THE FCST WAS
TO FOCUS PCPN CHCS TO THE EVENING WITH A CLEARING TREND FOR THE
OVRNGT HOURS. BY THE MIDDLE OF THE WEEK...THE UPR RDG IS PROGGED
TO HAVE RETROGRADED BACK TOWARD THE CNTRL PLAINS WTH THE MEAN FLOW
OVER THE GREAT LAKES TURNING MORE NW. WEAK HI PRES TO BE SITUATED
OVER THE WRN GREAT LAKES REGION ON WED...THUS A DECENT AMOUNT OF
SUNSHINE IS ANTICIPATED. 8H TEMPS TO STILL BE AROUND +20C...SO
TEMPS WL REMAIN RATHER WARM WITH A MINOR DROP IN DEW POINTS BEHIND
THE DEPARTED SFC TROF.
THERE ARE NOW CONCERNS FOR THU`S DRY FCST AS THE MDLS ARE
INDICATING THE NEXT MID-LEVEL SHORTWAVE TROF TO BE ROUNDING THE
CNTRL CONUS UPR RDG AND DIVING SE TOWARD WI. NOT SURE AT THIS
POINT WHETHER THIS POTENTIAL CONVECTION WOULD IMPACT ALL OF NE WI
OR DIVE SE ENUF TO ONLY AFFECT CNTRL WI. AT THIS POINT...FOLLOWED
THE CONSENSUS SOLUTION WHICH BRINGS A SLIGHT CHC POP TO MUCH OF
THE FCST AREA. TEMPS FOR WED LOOK TO BE SIMILAR TO WED WITH PLENTY
OF 80S TO GO AROUND.
ANOTHER AREA OF HI PRES IS EXPECTED TO BUILD SWD FROM CANADA
DURING THE THU NGT/FRI TIME PERIOD. DO NOT CARE FOR THE MINIMAL
POP ADVERTISED BY THE CONSENSUS SOLUTION AND PREFER TO GO DRY FOR
FRI WITH TEMPS GENERALLY IN THE 80-85 DEG RANGE. RETURN FLOW THEN
SETS UP OVER THE REGION NEXT WEEKEND WHICH WL LEAD TO WARMER
TEMPS...AN UPTICK IN HUMIDITY LEVELS AND THE POSSIBILITY OF WAA-
INDUCED PCPN CHCS. ATTM...ANY PCPN APPEARS TO BE WIDELY SCT AT
BEST WITH NO FOCUSING MECHANISM PRESENT.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1127 AM CDT SUN AUG 25 2013
STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
NORTH-CENTRAL WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING...
THEN SAG SOUTHWARD ACROSS THE AREA DURING THE EVENING INTO EARLY
MONDAY MORNING. SOME OF THE STRONGER STORMS COULD PRODUCE GUSTS
OVER 50 KNOTS AND HAIL OVER 1 INCH IN DIAMETER. 12Z TAFS SEEMED
TO HAVE A PRETTY GOOD HANDLE ON TIMING OF CONVECTION AND WILL MAKE
SOME MINOR ADJUSTMENTS THERE. GREATEST RISK OF SEVERE WEATHER SHOULD
BE NORTH AND WEST OF THE FOX VALLEY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........ECKBERG
SHORT TERM.....ESB
LONG TERM......KALLAS
AVIATION.......ECKBERG